Updates build.yml trigger to automatically start workflow when a release branch is created

Author: michael-hawker

.github/workflows/build.yml

@@ -6,9 +6,9 @@ name: CI
 
 # Controls when the action will run.
 on:
-  # Triggers the workflow on push or pull request events but only for the main branch
+  # Triggers the workflow on push or pull request events but only for the main or release branches
   push:
-    branches: [ main ]
+    branches: [ main, 'rel/*' ]
   pull_request:
     branches: [ main ]