Fix CI workflow: remove external checkout action, use auto-checkout, use python3 -m pytest

.gitea/workflows/ci.yml

@@ -10,14 +10,13 @@ jobs:
   test:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v4
       - name: Set up Python
         run: |
-          sudo apt-get update
-          sudo apt-get install -y python3 python3-pip python3-venv
+          apt-get update
+          apt-get install -y python3 python3-pip python3-venv
           python3 --version
           pip3 --version
       - name: Install package
         run: pip3 install -e . pytest pytest-asyncio
       - name: Run tests
-        run: pytest tests/ -v
+        run: python3 -m pytest tests/ -v