Update flake8 requirement from ~=4.0.1 to ~=6.1.0

Updates the requirements on [flake8](https://github.com/pycqa/flake8) to permit the latest version.
- [Commits](PyCQA/flake8@4.0.1...6.1.0)

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

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

requirements_test.txt

@@ -57,7 +57,7 @@ jax[cpu]==0.4.23
 # other
 pytest~=7.4.3
 pytest-flake8~=1.1.1
-flake8~=4.0.1
+flake8~=6.1.0
 pytest-mock~=3.10.0
 pytest-cov~=4.1.0
 requests~=2.31.0