Add job to check for all test-installation jobs

The added job runs if all the `test-installation` matrix jobs
ran and succeeded. The job is required to have a single job
that is used in branch protection rules so that updating the
protection rules is not needed each time we add or remove a job
from the matrix.

Signed-off-by: Daniel Zullo <[email protected]>

Author: daniel-zullo-frequenz

.github/workflows/ci.yaml

@@ -271,6 +271,19 @@ jobs:
           tags: localhost/test-installation
           push: false
 
+  # This job runs if all the `test-installation` matrix jobs ran and succeeded.
+  # It is only used to have a single job that we can require in branch
+  # protection rules, so we don't have to update the protection rules each time
+  # we add or remove a job from the matrix.
+  test-installation-all:
+    # The job name should match the name of the `test-installation` job.
+    name: Test package installation in different architectures
+    needs: ["test-installation"]
+    runs-on: ubuntu-20.04
+    steps:
+      - name: Return true
+        run: "true"
+
   test-docs:
     name: Test documentation website generation
     if: github.event_name != 'push'