Update pytest-mock to 1.6.0

[pyup-bot]

There's a new version of pytest-mock available.
You are currently using 1.5.0. I have updated it to 1.6.0

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

Changelog

1.6.0

---

• The original assertions raised by the various Mock.assert_* methods
  now appear in the failure message, in addition to the message obtained from
  pytest introspection.
  Thanks quodlibetor_ for the initial patch (79_).

.. _quodlibetor: https://github.com/quodlibetor

.. _79: pytest-dev/pytest-mock#79

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

Happy merging! 🤖

[codecov-io]

Codecov Report

Merging #7 into master will not change coverage.
The diff coverage is n/a.

@@          Coverage Diff          @@
##           master     #7   +/-   ##
=====================================
  Coverage     100%   100%           
=====================================
  Files           1      1           
  Lines          28     28           
=====================================
  Hits           28     28

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update 290216e...c834da0. Read the comment docs.