Bump mock from 4.0.2 to 5.1.0

Bumps [mock](https://github.com/testing-cabal/mock) from 4.0.2 to 5.1.0.
- [Changelog](https://github.com/testing-cabal/mock/blob/master/CHANGELOG.rst)
- [Commits](testing-cabal/mock@4.0.2...5.1.0)

---
updated-dependencies:
- dependency-name: mock
  dependency-type: direct:production
  update-type: version-update:semver-major
...

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

requirements.txt

@@ -9,7 +9,7 @@ djangorestframework==3.12.2
 drf-spectacular==0.15.1
 flake8==3.9.0
 gunicorn==20.1.0
-mock==4.0.2
+mock==5.1.0
 pysaml2
 python3-openid==3.1.0
 requests==2.31.0