Add 'check' task to CI that makes sure everything is green.

This allows to simply the branch protection steps, which in turn
makes it easier to upgrade CI without having to adjust the branch
protection conditions every time.

Signed-off-by: Felix Fontein <felix@fontein.de>

.github/workflows/cli.yml

@@ -122,3 +122,22 @@ jobs:
       - name: Run tests
         run: cargo test
         working-directory: ./functional-tests
+
+  # The 'check' job should depend on all other jobs so it's possible to configure branch protection only for 'check'
+  # instead of having to explicitly list all individual jobs that need to pass.
+  check:
+    if: always()
+
+    needs:
+      - build
+      - test
+
+    runs-on: ubuntu-latest
+
+    steps:
+      - name: Decide whether the needed jobs succeeded or failed
+        uses: re-actors/alls-green@05ac9388f0aebcb5727afa17fcccfecd6f8ec5fe # v1.2.2
+        with:
+          allowed-failures: docs, linters
+          allowed-skips: non-voting-flaky-job
+          jobs: ${{ toJSON(needs) }}