build(deps-dev): bump flake8 from 3.9.2 to 6.1.0

Bumps [flake8](https://github.com/pycqa/flake8) from 3.9.2 to 6.1.0.
- [Commits](PyCQA/flake8@3.9.2...6.1.0)

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

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