Bump flake8 from 4.0.1 to 5.0.3 in /requirements

Bumps [flake8](https://github.com/pycqa/flake8) from 4.0.1 to 5.0.3.
- [Release notes](https://github.com/pycqa/flake8/releases)
- [Commits](PyCQA/flake8@4.0.1...5.0.3)

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

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

Author: dependabot[bot]

requirements/lint.txt

@@ -1,3 +1,3 @@
 black==22.6.0
-flake8==4.0.1
+flake8==5.0.3
 isort==5.10.1