test: run pipeline on PR to test it

Author: Mark Brockhoff

.github/workflows/publish-testservice.yml

@@ -1,8 +1,11 @@
 name: Build and publish image of Testservice to quay.io
 
 on:
-  push:
+  # ToDo: This trigger should be removed before merging, it's just to test the Workflow
+  pull_request:
     branches: ["develop"]
+  push:
+    branches: ["main"]
 
 jobs:
   quay_publish: