Simplify example test Github Actions workflow

* Trigger test workflow on any push, whether that's a pull request
or a push to a branch

Author: dghubble

.github/workflows/test.yaml

@@ -1,9 +1,6 @@
 name: test
 on:
   push:
-    branches:
-      - main
-  pull_request:
 jobs:
   build:
     name: go