Update pytest-mock to 3.7.0

[pyup-bot]

This PR updates pytest-mock from 3.6.1 to 3.7.0.

Changelog

3.7.0

------------------

* Python 3.10 now officially supported.
* Dropped support for Python 3.6.

Links

• PyPI: https://pypi.org/project/pytest-mock
• Changelog: https://pyup.io/changelogs/pytest-mock/
• Repo: https://github.com/pytest-dev/pytest-mock/

[pyup-bot]

Closing this in favor of #57