ci: use github actions instead of gitlab-ci

.github/workflows/test.yml

@@ -0,0 +1,45 @@
+name: Test
+
+on: pull_request
+
+jobs:
+  lint:
+    name: Linting and formatting
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v3
+      - uses: actions/setup-python@v3
+        name: Install Python
+        with:
+          python-version: "3.x"
+
+      - name: Install tox
+        run: python -m pip install tox
+
+      - name: Run test suite
+        run: python -m tox -e flake8,black,yamllint
+
+  test_tox:
+    name: Run full tests
+    needs: lint
+    runs-on: ubuntu-latest
+
+    steps:
+      - uses: actions/checkout@v3
+      - uses: actions/setup-python@v3
+        name: Install Python
+        with:
+          python-version: "3.x"
+      - name: Install Node
+        uses: actions/setup-node@v3
+        with:
+          node-version: "lts"
+
+      - name: Install node modules
+        run: npm ci
+
+      - name: Install tox
+        run: python -m pip install tox
+
+      - name: Run test suite
+        run: python -m tox -e py3