Update flake8 requirement from ~=5.0.4 to ~=7.1.2

Updates the requirements on [flake8](https://github.com/pycqa/flake8) to permit the latest version.
- [Commits](PyCQA/flake8@5.0.4...7.1.2)

---
updated-dependencies:
- dependency-name: flake8
  dependency-type: direct:development
...

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

Author: dependabot[bot]

requirements-dev.txt

@@ -8,5 +8,5 @@
 # It only exists to keep the list of dependencies in a separate file from
 # setup.py.
 coverage ~=7.2
-flake8 ~=5.0.4
+flake8 ~=7.1.2
 pytest ~=7.4.4