GHA maintenance (#96)

.github/dependabot.yml

@@ -0,0 +1,10 @@
+---
+version: 2
+updates:
+  - package-ecosystem: "github-actions"
+    directory: "/"
+    schedule:
+      interval: weekly
+    open-pull-requests-limit: 3
+    labels:
+      - "skip-changelog"

.github/workflows/tox.yml

@@ -83,3 +83,14 @@ jobs:
           pip install tox
       - name: Test
         run: "tox -e ${{ matrix.tox_env }}"
+
+  check: # This job does nothing and is only used for the branch protection
+    if: always()
+    needs:
+      - build
+    runs-on: ubuntu-latest
+    steps:
+      - name: Decide whether the needed jobs succeeded or failed
+        uses: re-actors/alls-green@release/v1
+        with:
+          jobs: ${{ toJSON(needs) }}