Upgrade: bump flake8 from 3.9.1 to 3.9.2 (#29)

Bumps [flake8](https://gitlab.com/pycqa/flake8) from 3.9.1 to 3.9.2.
- [Release notes](https://gitlab.com/pycqa/flake8/tags)
- [Commits](https://gitlab.com/pycqa/flake8/compare/3.9.1...3.9.2)

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

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

Author: dependabot[bot]

requirements.txt

@@ -1,4 +1,4 @@
-flake8==3.9.1
+flake8==3.9.2
 mccabe==0.6.1
 pycodestyle==2.7.0
 pyflakes==2.3.1