Bump flake8 from 6.0.0 to 7.1.1

Bumps [flake8](https://github.com/pycqa/flake8) from 6.0.0 to 7.1.1.
- [Commits](PyCQA/flake8@6.0.0...7.1.1)

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

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

requirements-testing.txt

@@ -1,3 +1,3 @@
-flake8==6.0.0
+flake8==7.1.1
 pytest==6.2.4
 pytest-cov==2.12.1