Reformat container build workflow yaml

Use yaml instead of json syntax for array. It's easier to change and
diff if each item of an array is at its own line in the file.

.github/workflows/container.yml

@@ -2,10 +2,13 @@ name: Build and Push to Container Image
 
 on:
   push:
-    branches: [main]
-    tags: ['v24*']
+    branches:
+      - main
+    tags:
+      - 'v24*'
   pull_request:
-    branches: [main]
+    branches:
+      - main
   workflow_dispatch:
     inputs:
       ref-name: