Bump flake8 from 3.5.0 to 3.6.0
Bump flake8 from 3.5.0 to 3.6.0

Bumps [flake8](https://gitlab.com/pycqa/flake8) from 3.5.0 to 3.6.0.
- [Release notes](https://gitlab.com/pycqa/flake8/tags)
- [Commits](https://gitlab.com/pycqa/flake8/compare/3.5.0...3.6.0)

Signed-off-by: dependabot[bot] <5bdcd3c0d4d24ae3e71b3b452a024c6324c7e4bb@dependabot.com>
sloria/sphinx-issues