Bump flake8 from 3.8.2 to 3.8.3 (#36)

Bumps [flake8](https://gitlab.com/pycqa/flake8) from 3.8.2 to 3.8.3.
- [Release notes](https://gitlab.com/pycqa/flake8/tags)
- [Commits](https://gitlab.com/pycqa/flake8/compare/3.8.2...3.8.3)

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

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

Author: dependabot[bot]

requirements.txt

@@ -1,5 +1,5 @@
 entrypoints==0.3
-flake8==3.8.2
+flake8==3.8.3
 mccabe==0.6.1
 mypy==0.780
 pycodestyle==2.6.0