Bump flake8-requirements from 1.5 to 1.5.1 (#473)

Bumps [flake8-requirements](https://github.com/Arkq/flake8-requirements) from 1.5 to 1.5.1.
- [Release notes](https://github.com/Arkq/flake8-requirements/releases)
- [Commits](arkq/flake8-requirements@v1.5.0...v1.5.1)

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

Signed-off-by: dependabot[bot] <support@github.com>

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

requirements-dev.txt

@@ -7,7 +7,7 @@ flake8==3.9.2
 flake8-bandit==2.1.2
 flake8-bugbear==21.4.3
 flake8-import-order==0.18.1
-flake8-requirements==1.5
+flake8-requirements==1.5.1
 jinja2==3.0.1
 multidict==5.1.0
 mypy==0.910; implementation_name=="cpython"