FIX ruff versions in workflow

.github/workflows/ruff.yml

@@ -17,18 +17,23 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        python-version: ['3.9', '3.13']
+        python-version: ['py39']
 
     steps:
       - name: Checkout
         uses: actions/checkout@v4
         with:
           fetch-depth: 0
 
+      # Ruff does not need a specific python version installed
       - name: Install dependencies
         run: |
           python -m pip install -U ruff
 
       - name: Lint with Ruff
         run: |
           ruff check --target-version ${{ matrix.python-version }} --output-format=github
+
+      - name: Check format with Ruff
+        run: |
+          ruff format --check