pin flake8 version

.github/workflows/flake8.yaml

@@ -25,7 +25,7 @@ jobs:
  - name: Install flake8
  run: |
  python -m pip install --upgrade pip
- pip install flake8
+ pip install flake8==6.0.0
  - name: List changed files
  run: |
  git diff --compact-summary "origin/$GITHUB_BASE_REF"