add test build

.github/workflows/release.yml

@@ -14,6 +14,9 @@ name: Create and publish a Docker image
 on:
   release:
     types: [published]
+  push:
+    branches:
+      - 'merge-upstream-2.2.2-dev'
 
 env:
   REGISTRY: ghcr.io
@@ -50,7 +53,8 @@ jobs:
         with:
           platforms: linux/amd64,linux/arm64/v8
           build-args: |
-            ETHERPAD_PLUGINS=kitsteam/ep_comments_page kitsteam/ep_push2delete ep_image_upload ep_embedded_hyperlinks2 ep_headings2 kitsteam/ep_delete_after_delay kitsteam/ep_delete_empty_pads ep_align ep_font_color ep_helmet ep_font_size ep_disable_imports
+            ETHERPAD_PLUGINS=ep_image_upload ep_embedded_hyperlinks2 ep_headings2 ep_align ep_font_color ep_helmet ep_font_size ep_disable_imports |
+            ETHERPAD_GITHUB_PLUGINS=kitsteam/ep_comments_page kitsteam/ep_push2delete kitsteam/ep_delete_after_delay kitsteam/ep_delete_empty_pads
           push: true
           tags: ${{ steps.meta.outputs.tags }}
           labels: ${{ steps.meta.outputs.labels }}