Update workflow events

Author: shanejbrown

.github/workflows/build.yaml

@@ -1,7 +1,12 @@
 name: Build
 on:
-  - push
-  - pull_request
+  # Only run workflow when there is push to main or when there is a pull request to main
+  push:
+    branches:
+      - main
+  pull_request:
+    branches:
+      - main
 jobs:
   test:
     # When running with act (https://github.com/nektos/act), these lines need to be appended with the ACT variable