add all-green CI job (#1283)

Author: mhils

.github/workflows/ci.yml

@@ -84,3 +84,14 @@ jobs:
         run: |
           curl -o codecov.sh -f https://codecov.io/bash || curl -o codecov.sh -f https://codecov.io/bash || curl -o codecov.sh -f https://codecov.io/bash
           bash codecov.sh -n "tox -e ${{ matrix.TEST.TOXENV }} on ${{ matrix.TEST.CONTAINER }}"
+
+  all-green:
+    runs-on: ubuntu-latest
+    needs: [linux, linux-docker]
+    if: ${{ always() }}
+    timeout-minutes: 3
+    steps:
+      - name: Decide whether the needed jobs succeeded or failed
+        uses: re-actors/alls-green@05ac9388f0aebcb5727afa17fcccfecd6f8ec5fe # v1.2.2
+        with:
+          jobs: ${{ toJSON(needs) }}