CI: (deps): Bump the flake8 group in /ci with 1 update

Bumps the flake8 group in /ci with 1 update: [flake8-requirements](https://github.com/Arkq/flake8-requirements).


Updates `flake8-requirements` from 2.0.2 to 2.1.0
- [Commits](arkq/flake8-requirements@v2.0.2...v2.1.0)

---
updated-dependencies:
- dependency-name: flake8-requirements
  dependency-type: direct:production
  update-type: version-update:semver-minor
  dependency-group: flake8
...

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

ci/linting_requirements.txt

@@ -7,7 +7,7 @@ pyflakes==3.2.0
 flake8-continuation==1.0.5
 flake8-isort==6.1.1
 isort==5.13.2
-flake8-requirements==2.0.2
+flake8-requirements==2.1.0
 
 flake8-rst-docstrings==0.3.0