Bump pytest-mock from 1.11.1 to 3.5.1 in /requirements

Bumps [pytest-mock](https://github.com/pytest-dev/pytest-mock) from 1.11.1 to 3.5.1.
- [Release notes](https://github.com/pytest-dev/pytest-mock/releases)
- [Changelog](https://github.com/pytest-dev/pytest-mock/blob/master/CHANGELOG.rst)
- [Commits](pytest-dev/pytest-mock@v1.11.1...v3.5.1)

Signed-off-by: dependabot[bot] <support@github.com>

requirements/requirements_dev.txt

@@ -8,7 +8,7 @@ pytest
 pytest-cov
 pytest-django
 pytest-pythonpath
-pytest-mock==1.11.1
+pytest-mock==3.5.1
 pytest-timeout
 pytest-xdist==1.34.0 # 2.0.0 broke zuul for some reason
 tox  # for awxkit