Add ruff action

Author: david-pl

.github/workflows/docstrings.yml

@@ -13,5 +13,6 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v5
+      - uses: chartboost/ruff-action@v1
       - name: Check docstrings
         run: ruff check --select="D" src/