.github: run ruff in CI

Author: jelly

.github/workflows/main.yml

@@ -16,7 +16,10 @@ jobs:
     - name: Install dependencies
       run: |
         python -m pip install --upgrade pip
-        pip install -r requirements.txt && pip install -r requirements_test.txt
+        pip install -r requirements.txt && pip install -r requirements_test.txt && pip install ruff
+    - name: Run ruff
+      run: |
+        ruff check .
     - name: Lint with flake8
       run: |
         make lint