Start using a Gitea action for continuous testing

.gitea/workflows/ci.yaml

@@ -0,0 +1,24 @@
+name: Continuous integration
+
+on:
+  push:
+    branches:
+    - main
+
+jobs:
+  run:
+    runs-on: ubuntu-latest
+    steps:
+    - uses: https://github.com/actions/checkout@v4
+    - name: Set up Python
+      uses: https://github.com/actions/setup-python@v5
+      with:
+        python-version: 3.12
+    - name: Install ourself
+      run: pip install -e .
+    - name: Run static analysis
+      run: hatch run lint-check
+    - name: Check types
+      run: hatch run types-check
+    - name: Run tests
+      run: hatch run test