Update python-dateutil to 2.8.1

[pyup-bot]

This PR updates python-dateutil from 2.6.1 to 2.8.1.

Changelog

2.8.1

==========================

Data updates
------------

- Updated tzdata version to 2019c.


Bugfixes
--------

- Fixed a race condition in the ``tzoffset`` and ``tzstr`` "strong" caches on
Python 2.7. Reported by kainjow (gh issue 901).
- Parsing errors will now raise ``ParserError``, a subclass of ``ValueError``,
which has a nicer string representation. Patch by gfyoung (gh pr 881).
- ``parser.parse`` will now raise ``TypeError`` when ``tzinfos`` is passed a
type that cannot be interpreted as a time zone. Prior to this change, it
would raise an ``UnboundLocalError`` instead.  Patch by jbrockmendel (gh pr
891).
- Changed error message raised when when passing a ``bytes`` object as the time
zone name to gettz in Python 3.  Reported and fixed by labrys () (gh issue
927, gh pr 935).
- Changed compatibility logic to support a potential Python 4.0 release. Patch
by Hugo van Kemenade (gh pr 950).
- Updated many modules to use ``tz.UTC`` in favor of ``tz.tzutc()`` internally,
to avoid an unnecessary function call. (gh pr 910).
- Fixed issue where ``dateutil.tz`` was using a backported version of
``contextlib.nullcontext`` even in Python 3.7 due to a malformed import
statement. (gh pr 963).


Tests
-----

- Switched from using assertWarns to using pytest.warns in the test suite. (gh
pr 969).
- Fix typo in setup.cfg causing PendingDeprecationWarning to not be explicitly
specified as an error in the warnings filter. (gh pr 966)
- Fixed issue where ``test_tzlocal_offset_equal`` would fail in certain
environments (such as FreeBSD) due to an invalid assumption about what time
zone names are provided. Reported and fixed by Kubilay Kocak (gh issue 918,
pr 928).
- Fixed a minor bug in ``test_isoparser`` related to ``bytes``/``str``
handling. Fixed by fhuang5 (gh issue 776, gh pr 879).
- Explicitly listed all markers used in the pytest configuration. (gh pr 915)
- Extensive improvements to the parser test suite, including the adoption of
``pytest``-style tests and the addition of parametrization of several test
cases. Patches by jbrockmendel (gh prs 735, 890, 892, 894).
- Added tests for tzinfos input types. Patch by jbrockmendel (gh pr 891).
- Fixed failure of test suite when changing the TZ variable is forbidden.
Patch by shadchin (gh pr 893).
- Pinned all test dependencies on Python 3.3. (gh prs 934, 962)


Documentation changes
---------------------

- Fixed many misspellings, typos and styling errors in the comments and
documentation. Patch by Hugo van Kemenade (gh pr 952).


Misc
----

- Added Python 3.8 to the trove classifiers. (gh pr 970)
- Moved as many keys from ``setup.py`` to ``setup.cfg`` as possible.  Fixed by
FakeNameSE, aquinlan82, jachen20, and gurgenz221 (gh issue 871, gh pr
880).
- Reorganized ``parser`` methods by functionality. Patch by jbrockmendel (gh
pr 882).
- Switched ``release.py`` over to using ``pep517.build`` for creating releases,
rather than direct invocations of ``setup.py``. Fixed by smeng10 (gh issue
869, gh pr 875).
- Added a "build" environment into the tox configuration, to handle dependency
management when making releases. Fixed by smeng10 (gh issue 870,r
gh pr 876).
- GH 916, GH 971

2.8.0

==========================

Data updates
------------

- Updated tzdata version to to 2018i.


Features
--------

- Added support for ``EXDATE`` parameters when parsing ``rrule`` strings.
Reported by mlorant (gh issue 410), fixed by nicoe (gh pr 859).
- Added support for sub-minute time zone offsets in Python 3.6+.
Fixed by cssherry (gh issue 582, pr 763)
- Switched the ``tzoffset``, ``tzstr`` and ``gettz`` caches over to using weak
references, so that the cache expires when no other references to the
original ``tzinfo`` objects exist. This cache-expiry behavior is not
guaranteed in the public interface and may change in the future. To improve
performance in the case where transient references to the same time zones
are repeatedly created but no strong reference is continuously held, a
smaller "strong value" cache was also added. Weak value cache implemented by
cs-cordero (gh pr 672, 801), strong cache added by
Gökçen Nurlu (gh issue 691, gh pr 761)


Bugfixes
--------

- Add support for ISO 8601 times with comma as the decimal separator in the
``dateutil.parser.isoparse`` function. (gh pr 721)
- Changed handling of ``T24:00`` to be compliant with the standard. ``T24:00``
now represents midnight on the *following* day.
Fixed by cheukting (gh issue 658, gh pr 751)
- Fixed an issue where ``isoparser.parse_isotime`` was unable to handle the
``24:00`` variant representation of midnight. (gh pr 773)
- Added support for more than 6 fractional digits in `isoparse`.
Reported and fixed by jayschwa (gh issue 786, gh pr 787).
- Added 'z' (lower case Z) as valid UTC time zone in isoparser.
Reported by cjgibson (gh issue 820). Fixed by Cheukting (gh pr 822)
- Fixed a bug with base offset changes during DST in ``tzfile``, and refactored
the way base offset changes are detected. Originally reported on
Stack Overflow by MartinThoma. (gh issue 812, gh pr 810)
- Fixed error condition in ``tz.gettz`` when a non-ASCII timezone is passed on
Windows in Python 2.7. (gh issue 802, pr 861)
- Improved performance and inspection properties of ``tzname`` methods.
(gh pr 811)
- Removed unnecessary binary_type compatibility shims.
Added by jdufresne (gh pr 817)
- Changed ``python setup.py test`` to print an error to ``stderr`` and exit
with 1 instead of 0. Reported and fixed by hroncok (gh pr 814)
- Added a ``pyproject.toml`` file with build requirements and an explicitly
specified build backend. (gh issue 736, gh prs 746, 863)


Documentation changes
---------------------

- Added documentation for the ``rrule.rrulestr`` function.
Fixed by prdickson (gh issue 623, gh pr 762)
- Add documentation for the ``dateutil.tz.win`` module and mocked out certain
Windows-specific modules so that autodoc can still be run on non-Windows
systems. (gh issue 442, pr 715)
- Added changelog to documentation. (gh issue 692, gh pr 707)
- Improved documentation on the use of ``until`` and ``count`` parameters in
``rrule``. Fixed by lucaferocino (gh pr 755).
- Added an example of how to use a custom ``parserinfo`` subclass to parse
non-standard datetime formats in the examples documentation for ``parser``.
Added by prdickson (gh 753)
- Expanded the description and examples in the ``relativedelta`` class.
Contributed by andrewcbennett (gh pr 759)
- Improved the contributing documentation to clarify where to put new changelog
files. Contributed by andrewcbennett (gh pr 757)
- Fixed a broken doctest in the ``relativedelta`` module.
Fixed by nherriot (gh pr 758).
- Reorganized ``dateutil.tz`` documentation and fixed issue with the
``dateutil.tz`` docstring. (gh pr 714)


Misc
----

- GH 720, GH 723, GH 726, GH 727, GH 740, GH 750, GH 760, GH 767,
GH 772, GH 773, GH 780, GH 784, GH 785, GH 791, GH 799, GH 813,
GH 836, GH 839, GH 857

2.7.5

==========================

Data updates
------------

- Update tzdata to 2018g

2.7.4

==========================

Data updates
------------

- Updated tzdata version to 2018f.

2.7.3

==========================

Data updates
------------

- Update tzdata to 2018e. (gh pr 710)


Bugfixes
--------

- Fixed an issue where ``parser.parse`` would raise ``Decimal``-specific errors
instead of a standard ``ValueError`` if certain malformed values were parsed
(e.g. ``NaN`` or infinite values). Reported and fixed by
amureki (gh issue 662, gh pr 679).
- Fixed issue in ``parser`` where a ``tzinfos`` call explicitly returning
``None`` would throw a ``ValueError``.
Fixed by parsethis (gh issue 661, gh pr 681)
- Fixed incorrect parsing of certain dates earlier than 100 AD when represented
in the form "%B.%Y.%d", e.g. "December.0031.30". (gh issue 687, pr 700)
- Added time zone inference when initializing an ``rrule`` with a specified
``UNTIL`` but without an explicitly specified ``DTSTART``; the time zone
of the generated ``DTSTART`` will now be taken from the ``UNTIL`` rule.
Reported by href (gh issue 652). Fixed by absreim (gh pr 693).

Documentation changes
---------------------

- Corrected link syntax and updated URL to https for ISO year week number
notation in relativedelta examples. (gh issue 670, pr 711)
- Add doctest examples to tzfile documentation. Done by weatherpattern and
pganssle (gh pr 671)
- Updated the documentation for relativedelta. Removed references to tuple
arguments for weekday, explained effect of weekday(_, 1) and better explained
the order of operations that relativedelta applies. Fixed by kvn219
huangy22 and ElliotJH (gh pr 673)
- Added changelog to documentation. (gh issue 692, gh pr 707)
- Changed order of keywords in rrule docstring. Reported and fixed by
rmahajan14 (gh issue 686, gh pr 695).
- Added documentation for ``dateutil.tz.gettz``. Reported by pganssle (gh
issue 647). Fixed by weatherpattern (gh pr 704)
- Cleaned up malformed RST in the ``tz`` documentation. (gh issue 702, gh pr
706)
- Changed the default theme to ``sphinx_rtd_theme``, and changed the sphinx
configuration accordingly. (gh pr 707)
- Reorganized ``dateutil.tz`` documentation and fixed issue with the
``dateutil.tz`` docstring. (gh pr 714)


Misc
----

- GH 674, GH 688, GH 699

2.7.2

==========================

Bugfixes
--------

- Fixed an issue with the setup script running in non-UTF-8 environment.
Reported and fixed by gergondet (gh pr 651)


Misc
----

- GH 655

2.7.1

===========================

Data updates
------------

- Updated tzdata version to 2018d.


Bugfixes
--------

- Fixed issue where parser.parse would occasionally raise
decimal.Decimal-specific error types rather than ValueError. Reported by
amureki (gh issue 632). Fixed by pganssle (gh pr 636).
- Improve error message when rrule's dtstart and until are not both naive or
both aware. Reported and fixed by ryanpetrello (gh issue 633, gh pr 634)


Misc
----

- GH 644, GH 648

2.7.0

=============
- Dropped support for Python 2.6 (gh pr 362 by jdufresne)
- Dropped support for Python 3.2 (gh pr 626)
- Updated zoneinfo file to 2018c (gh pr 616)
- Changed licensing scheme so all new contributions are dual licensed under
Apache 2.0 and BSD. (gh pr 542, issue 496)
- Added __all__ variable to the root package. Reported by tebriel
(gh issue 406), fixed by mariocj89 (gh pr 494)
- Added python_requires to setup.py so that pip will distribute the right
version of dateutil. Fixed by jakec-github (gh issue 537, pr 552)
- Added the utils submodule, for miscellaneous utilities.
- Added within_delta function to utils - added by justanr (gh issue 432,
gh pr 437)
- Added today function to utils (gh pr 474)
- Added default_tzinfo function to utils (gh pr 475), solving an issue
reported by nealmcb (gh issue 94)
- Added dedicated ISO 8601 parsing function isoparse (gh issue 424).
Initial implementation by pganssle in gh pr 489 and 622, with a
pre-release fix by kirit93 (gh issue 546, gh pr 573). 
- Moved parser module into parser/_parser.py and officially deprecated the use
of several private functions and classes from that module. (gh pr 501, 515)
- Tweaked parser error message to include rejected string format, added by
pbiering (gh pr 300)
- Add support for parsing bytesarray, reported by uckelman (gh issue 417) and
fixed by uckelman and pganssle (gh pr 514)
- Started raising a warning when the parser finds a timezone string that it
cannot construct a tzinfo instance for (rather than succeeding with no
indication of an error). Reported and fixed by jbrockmendel (gh pr 540)
- Dropped the use of assert in the parser. Fixed by jbrockmendel (gh pr 502)
- Fixed to assertion logic in parser to support dates like '2015-15-May',
reported and fixed by jbrockmendel (gh pr 409)
- Fixed IndexError in parser on dates with trailing colons, reported and fixed
by jbrockmendel (gh pr 420)
- Fixed bug where hours were not validated, leading to improper parse. Reported
by heappro (gh pr 353), fixed by jbrockmendel (gh pr 482)
- Fixed problem parsing strings in %b-%Y-%d format. Reported and fixed by
jbrockmendel (gh pr 481)
- Fixed problem parsing strings in the %d%B%y format. Reported by asishm
(gh issue 360), fixed by jbrockmendel (gh pr 483)
- Fixed problem parsing certain unambiguous strings when year <99 (gh pr 510).
Reported by alexwlchan (gh issue 293).
- Fixed issue with parsing an unambiguous string representation of an ambiguous
datetime such that if possible the correct value for fold is set. Fixes
issue reported by JordonPhillips and pganssle (gh issue 318, 320,
gh pr 517)
- Fixed issue with improper rounding of fractional components. Reported by
dddmello (gh issue 427), fixed by m-dz (gh pr 570)
- Performance improvement to parser from removing certain min() calls. Reported
and fixed by jbrockmendel (gh pr 589)
- Significantly refactored parser code by jbrockmendel (gh prs 419, 436,
490, 498, 539) and pganssle (gh prs 435, 468)
- Implemented of __hash__ for relativedelta and weekday, reported and fixed
by mrigor (gh pr 389) 
- Implemented __abs__ for relativedelta. Reported by binnisb and pferreir
(gh issue 350, pr 472)
- Fixed relativedelta.weeks property getter and setter to work for both
negative and positive values. Reported and fixed by souliane (gh issue 459,
pr 460)
- Fixed issue where passing whole number floats to the months or years
arguments of the relativedelta constructor would lead to errors during
addition. Reported by arouanet (gh pr 411), fixed by lkollar (gh pr 553)
- Added a pre-built tz.UTC object representing UTC (gh pr 497)
- Added a cache to tz.gettz so that by default it will return the same object
for identical inputs. This will change the semantics of certain operations
between datetimes constructed with tzinfo=tz.gettz(...). (gh pr 628)
- Changed the behavior of tz.tzutc to return a singleton (gh pr 497, 504)
- Changed the behavior of tz.tzoffset to return the same object when passed the
same inputs, with a corresponding performance improvement (gh pr 504)
- Changed the behavior of tz.tzstr to return the same object when passed the
same inputs. (gh pr 628)
- Added .instance alternate constructors for tz.tzoffset and tz.tzstr, to
allow the construction of a new instance if desired. (gh pr 628)
- Added the tz.gettz.nocache function to allow explicit retrieval of a new
instance of the relevant tzinfo. (gh pr 628)
- Expand definition of tz.tzlocal equality so that the local zone is allow
equality with tzoffset and tzutc. (gh pr 598)
- Deprecated the idiosyncratic tzstr format mentioned in several examples but
evidently designed exclusively for dateutil, and very likely not used by
any current users. (gh issue 595, gh pr 606)
- Added the tz.resolve_imaginary function, which generates a real date from
an imaginary one, if necessary. Implemented by Cheukting (gh issue 339,
gh pr 607)
- Fixed issue where the tz.tzstr constructor would erroneously succeed if
passed an invalid value for tzstr. Fixed by pablogsal (gh issue 259,
gh pr 581)
- Fixed issue with tz.gettz for TZ variables that start with a colon. Reported
and fixed by lapointexavier (gh pr 601)
- Added a lock to tz.tzical's cache. Reported and fixed by Unrud (gh pr 430) 
- Fixed an issue with fold support on certain Python 3 implementations that
used the pre-3.6 pure Python implementation of datetime.replace, most
notably pypy3 (gh pr 446).
- Added support for VALUE=DATE-TIME for DTSTART in rrulestr. Reported by potuz
(gh issue 401) and fixed by Unrud (gh pr 429)
- Started enforcing that within VTIMEZONE, the VALUE parameter can only be
omitted or DATE-TIME, per RFC 5545. Reported by Unrud (gh pr 439)
- Added support for TZID parameter for DTSTART in rrulestr. Reported and
fixed by ryanpetrello (gh issue 614, gh pr 624)
- Added 'RRULE:' prefix to rrule strings generated by rrule.__str__, in
compliance with the RFC. Reported by AndrewPashkin (gh issue 86), fixed by
jarondl and mlorant (gh pr 450)
- Switched to setuptools_scm for version management, automatically calculating
a version number from the git metadata. Reported by jreback (gh issue 511),
implemented by Sulley38 (gh pr 564)
- Switched setup.py to use find_packages, and started testing against pip
installed versions of dateutil in CI. Fixed issue with parser import
discovered by jreback in pandas-dev/pandas18141. (gh issue 507, pr 509)
- Switched test suite to using pytest (gh pr 495)
- Switched CI over to use tox. Fixed by gaborbernat (gh pr 549)
- Added a test-only dependency on freezegun. (gh pr 474)
- Reduced number of CI builds on Appveyor. Fixed by kirit93 (gh issue 529,
gh pr 579)
- Made xfails strict by default, so that an xpass is a failure. (gh pr 567)
- Added a documentation generation stage to tox and CI. (gh pr 568)
- Added an explicit warning when running python setup.py explaining how to run
the test suites with pytest. Fixed by lkollar. (gh issue 544, gh pr 548)
- Added requirements-dev.txt for test dependency management (gh pr 499, 516)
- Fixed code coverage metrics to account for Windows builds (gh pr 526)
- Fixed code coverage metrics to NOT count xfails. Fixed by gaborbernat
(gh issue 519, gh pr 563)
- Style improvement to zoneinfo.tzfile that was confusing to static type
checkers. Reported and fixed by quodlibetor (gh pr 485)
- Several unused imports were removed by jdufresne. (gh pr 486)
- Switched ``isinstance(*, collections.Callable)`` to callable, which is available
on all supported Python versions. Implemented by jdufresne (gh pr 612)
- Added CONTRIBUTING.md (gh pr 533)
- Added AUTHORS.md (gh pr 542)
- Corrected setup.py metadata to reflect author vs. maintainer, (gh issue 477,
gh pr 538)
- Corrected README to reflect that tests are now run in pytest. Reported and
fixed by m-dz (gh issue 556, gh pr 557)
- Updated all references to RFC 2445 (iCalendar) to point to RFC 5545. Fixed
by mariocj89 (gh issue 543, gh pr 555)
- Corrected parse documentation to reflect proper integer offset units,
reported and fixed by abrugh (gh pr 458)
- Fixed dangling parenthesis in tzoffset documentation (gh pr 461)
- Started including the license file in wheels. Reported and fixed by
jdufresne (gh pr 476)
- Indentation fixes to parser docstring by jbrockmendel (gh pr 492)
- Moved many examples from the "examples" documentation into their appropriate
module documentation pages. Fixed by Tomasz-Kluczkowski and jakec-github
(gh pr 558, 561)
- Fixed documentation so that the parser.isoparse documentation displays.
Fixed by alexchamberlain (gh issue 545, gh pr 560)
- Refactored build and release sections and added setup instructions to
CONTRIBUTING. Reported and fixed by kynan (gh pr 562)
- Cleaned up various dead links in the documentation. (gh pr 602, 608, 618)

Links

• PyPI: https://pypi.org/project/python-dateutil
• Changelog: https://pyup.io/changelogs/python-dateutil/
• Docs: https://dateutil.readthedocs.io