Bump flake8 from 5.0.4 to 6.0.0

Bumps [flake8](https://github.com/pycqa/flake8) from 5.0.4 to 6.0.0.
- [Release notes](https://github.com/pycqa/flake8/releases)
- [Commits](PyCQA/flake8@5.0.4...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>

test-requirements.txt

@@ -1,5 +1,5 @@
 reportlab==3.6.11
-flake8==5.0.4
+flake8==6.0.0
 pytest==7.2.0
 pytest-asyncio==0.16.0;python_version<"3.7"
 pytest-asyncio==0.20.1;python_version>="3.7"