Run CI on PR (#1)

In this way, we can test changes before pushing to main.

.github/workflows/push-image.yml → .github/workflows/build-and-publish.yml

@@ -1,11 +1,16 @@
-name: Create and publish Packages
+name: Build and publish Images/Packages
 
 on:
   push:
     branches:
       - main
     tags:
       - "v*.*.*"
+  pull_request:
+    branches:
+      - main
+
+concurrency: build_and_publish_concurrency_group-${{ github.event.pull_request.number || github.ref_name }}
 
 env:
   IMAGE_NAME: ${{ github.repository }}