Introduce a `check` CI job for branch protection (#11434)

This patch adds a special check-job that produces a clear failure or
success status based on how the dependent jobs are doing. It is
possible to use it in GitHub's branch protection instead of having to
manually add and remove individual job names via the repo settings.

https://github.com/marketplace/actions/alls-green#why

1 files changed, 31 insertions, 0 deletions

diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index c43b7dabb..0f0d0a9bb 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -284,3 +284,34 @@ jobs:
           -m integration
           --verbose --numprocesses auto --showlocals
           --durations=5
+
+  check:  # This job does nothing and is only used for the branch protection
+    if: always()
+
+    needs:
+      - determine-changes
+      - docs
+      - packaging
+      - pre-commit
+      - tests-unix
+      - tests-windows
+      - tests-zipapp
+      - tests-importlib-metadata
+      - vendoring
+
+    runs-on: ubuntu-latest
+
+    steps:
+      - name: Decide whether the needed jobs succeeded or failed
+        uses: re-actors/alls-green@release/v1
+        with:
+          allowed-skips: >-
+            ${{
+              (
+                needs.determine-changes.outputs.vendoring != 'true'
+                && github.event_name == 'pull_request'
+              )
+              && 'vendoring'
+              || ''
+            }}
+          jobs: ${{ toJSON(needs) }}