Set up ruff

Author: EvertBunschoten

.github/workflows/regression.yml

@@ -59,7 +59,13 @@ jobs:
     name: Check formatting
     runs-on: ubuntu-latest
     steps:
-      - name: Whitespaces check
-        uses: astral-sh/ruff-action@v3
-      - run: ruff check --select W291
-      
+      - name: Checkout code
+        uses: actions/checkout@v4
+      - name: Set up Python
+        uses: actions/setup-python@v5
+        with:
+          python-version: '3.13'
+      - name: Install Ruff
+        run: pip install ruff
+      - name: Run Ruff
+        run: ruff check .