Enable PR checks for regular branch builds to test them

.github/workflows/trigger_on_pull_request.yml

@@ -1,5 +1,14 @@
 name: PR Checks
-on: [ pull_request ]
+
+# TODO: change again after testing
+#on: [ pull_request ]
+on:
+  push:
+    branches:
+      - '*'         # matches every branch that doesn't contain a '/'
+      - '*/*'       # matches every branch containing a single '/'
+      - '**'        # matches every branch
+      - '!master'   # excludes master
 
 concurrency:
   group: ci-${{github.actor}}-${{github.head_ref || github.run_number}}-${{github.ref}}-trigger_on_pull_request