Lint with ruff in CI

Author: sveinbjornt

.github/workflows/python-package.yml

@@ -22,6 +22,10 @@ jobs:
       uses: actions/setup-python@v5
       with:
         python-version: ${{ matrix.python-version }}
+    - name: Lint with ruff
+      run: |
+        uv pip install --system ruff
+        ruff check src/icegrams
     - name: Install dependencies
       run: |
         python -m pip install uv