build(deps): bump flake8 from 4.0.1 to 5.0.4 (#174)

Bumps [flake8](https://github.com/pycqa/flake8) from 4.0.1 to 5.0.4.
- [Release notes](https://github.com/pycqa/flake8/releases)
- [Commits](PyCQA/flake8@4.0.1...5.0.4)

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

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

requirements_testing.txt

@@ -1,4 +1,4 @@
-flake8==4.0.1
+flake8==5.0.4
 isort==5.10.1
 mypy==0.960
 pytest-click==1.1.0