Bump flake8 from 3.9.2 to 7.0.0

Bumps [flake8](https://github.com/pycqa/flake8) from 3.9.2 to 7.0.0.
- [Commits](PyCQA/flake8@3.9.2...7.0.0)

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

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

requirements.txt

@@ -9,7 +9,7 @@ botorch
 gauche
 pytest==6.2.5
 pytest-cov==5.0.0
-flake8==3.9.2
+flake8==7.0.0
 mypy==0.910
 microstructpy
 pyglview