Limit branches/tags of container build

Limit branch

.github/workflows/containers.yml

@@ -1,9 +1,11 @@
 name: Build and push containers
 
 on:
-  # Automatically triggered by a testing workflow passing
+  # Automatically triggered by a testing workflow passing, but this is only checked when it lands in the `master`/default branch
   workflow_run:
     workflows: ["ChangeDetection.io Test"]
+    branches: [master]
+    tags: ['0.*']
     types: [completed]
 
   # Or a new tagged release
@@ -24,6 +26,7 @@ jobs:
         echo c: ${{ github.event.workflow_run.conclusion }}
         echo r: ${{ github.event.workflow_run }}
         echo tname: "${{ github.event.release.tag_name }}"
+        echo headbranch: -${{ github.event.workflow_run.head_branch }}-
         set
 
   build-push-containers: