Bump mock from 2.0.0 to 3.0.5

Bumps [mock](https://github.com/testing-cabal/mock) from 2.0.0 to 3.0.5.
- [Release notes](https://github.com/testing-cabal/mock/releases)
- [Changelog](https://github.com/testing-cabal/mock/blob/master/CHANGELOG.rst)
- [Commits](testing-cabal/mock@2.0.0...3.0.5)

Signed-off-by: dependabot[bot] <[email protected]>

Author: dependabot-preview[bot]

requirements.txt

@@ -3,7 +3,7 @@ requests==2.20.1
 pyjwt==1.7.1
 gitpython==2.1.12
 there==0.0.9
-mock==2.0.0
+mock==3.0.5
 cryptography==2.3.1
 friendlyautopep8==0.0.4
 yieldbreaker==0.0.1