Update sphinx to 1.7.1

[pyup-bot]

There's a new version of sphinx available.
You are currently using 1.7.0. I have updated it to 1.7.1

These links might come in handy: PyPI | Changelog | Homepage

Changelog

1.7.1

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

Deprecated

• 4623: sphinx.build_main() is deprecated. Use
  sphinx.cmd.build.build_main() instead.
• autosummary: The interface of sphinx.ext.autosummary.get_documenter() has
  been changed (Since 1.7.0)
• 4664: sphinx.ext.intersphinx.debug() is deprecated. Use
  sphinx.ext.intersphinx.inspect_main() instead.

Bugs fixed

• 4608: epub: Invalid meta tag is generated
• 4260: autodoc: keyword only argument separator is not disappeared if it is
  appeared at top of the argument list
• 4622: epub: :confval:epub_scheme does not effect to content.opf
• 4627: graphviz: Fit graphviz images to page
• 4617: quickstart: PROJECT_DIR argument is required
• 4623: sphinx.build_main no longer exists in 1.7.0
• 4615: The argument of sphinx.build has been changed in 1.7.0
• autosummary: The interface of sphinx.ext.autosummary.get_documenter() has
  been changed
• 4630: Have order on msgids in sphinx.pot deterministic
• 4563: autosummary: Incorrect end of line punctuation detection
• 4577: Enumerated sublists with explicit start with wrong number
• 4641: A external link in TOC cannot contain "?" with :glob: option
• C++, add missing parsing of explicit casts and typeid in expression parsing.
• C++, add missing parsing of this in expression parsing.
• 4655: Fix incomplete localization strings in Polish
• 4653: Fix error reporting for parameterless ImportErrors
• 4664: Reading objects.inv fails again
• 4662: any refs with term targets crash when an ambiguity is
  encountered

Got merge conflicts? Close this PR and delete the branch. I'll create a new PR for you.

Happy merging! 🤖