Bump flake8 from 4.0.1 to 6.0.0 (#426)

Bumps [flake8](https://github.com/pycqa/flake8) from 4.0.1 to 6.0.0.
- [Release notes](https://github.com/pycqa/flake8/releases)
- [Commits](PyCQA/flake8@4.0.1...6.0.0)

---
updated-dependencies:
- dependency-name: flake8
  dependency-type: direct:production
  update-type: version-update:semver-major
...

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

requirements.txt

@@ -83,5 +83,5 @@ humanize==4.4.0
 pytest==8.2.0
 pytest-cov==3.0.0
 mccabe==0.6.1
-flake8==4.0.1
+flake8==6.0.0