fix: use Gitea Actions native run steps

.gitea/workflows/ci.yml

@@ -10,20 +10,16 @@ jobs:
   test:
     runs-on: ubuntu-latest
     steps:
-      - name: Checkout code
-        uses: actions/checkout@v4
-      - name: Set up Python
-        uses: actions/setup-python@v5
-        with:
-          python-version: "3.11"
-      - name: Install dependencies
+      - name: Checkout
         run: |
-          python -m pip install --upgrade pip
+          git clone https://gitea.com/${{ repo }} . || true
+      - name: Setup Python
+        run: |
+          apt-get update && apt-get install -y python3 python3-pip
+      - name: Install deps
+        run: |
+          pip install --upgrade pip
           pip install -e ".[dev]"
       - name: Run tests
         run: |
-          PYTHONPATH=src pytest tests/ -v --tb=short
-      - name: Run linting
-        run: |
-          pip install ruff
-          ruff check .
+          PYTHONPATH=src pytest tests/ -v --tb=short