Bump mock from 4.0.2 to 4.0.3

Bumps [mock](https://github.com/testing-cabal/mock) from 4.0.2 to 4.0.3.
- [Release notes](https://github.com/testing-cabal/mock/releases)
- [Changelog](https://github.com/testing-cabal/mock/blob/master/CHANGELOG.rst)
- [Commits](testing-cabal/mock@4.0.2...4.0.3)

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

requirements-test.txt

@@ -5,6 +5,6 @@ pytest==6.1.2
 pytest-cov==2.10.1
 coverage==5.3 # pytest-cov
 pytest-xdist==2.1.0
-Mock==4.0.2
+Mock==4.0.3
 redis==3.5.3
 -e .[tests]