CI: Add proper dummy job we can depend on

Author: bastelfreak

.github/workflows/pr-testing.yml

@@ -121,6 +121,7 @@ jobs:
         run: clj-kondo --lint src test
 
   tests:
+    if: always()
     needs:
       - clojure-tests
       - rspec-tests
@@ -129,4 +130,7 @@ jobs:
     runs-on: ubuntu-24.04
     name: Test suite
     steps:
-      - run: echo Test suite completed
+      - name: Decide whether the needed jobs succeeded or failed
+        uses: re-actors/alls-green@release/v1
+        with:
+          jobs: ${{ toJSON(needs) }}