Bump the all-dependencies group with 1 update

Updates the requirements on [flake8](https://github.com/pycqa/flake8) to permit the latest version.

Updates `flake8` to 7.0.0
- [Commits](PyCQA/flake8@6.1.0...7.0.0)

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

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

requirements-test.txt

@@ -2,7 +2,7 @@
 codecov~=2.1
 cov-core~=1.15
 coverage~=7.4
-flake8~=6.1
+flake8~=7.0
 mock~=5.1
 pytest~=7.4
 pytest-cov~=4.1