Bump mock from 4.0.2 to 4.0.3 (#15)

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[bot] <support@github.com>

Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

test_requirements.txt

@@ -2,4 +2,4 @@ pytest==6.1.2
 pytest-asyncio==0.14.0
 pytest-testdox==2.0.1
 pytest-randomly==3.5.0
-mock==4.0.2
+mock==4.0.3