apply CI to all branches

Author: teverett

.github/workflows/main.yml

@@ -2,9 +2,9 @@ name: CI
 
 on:
   push:
-    branches: [ master ]
+    branches: [ '*' ]
   pull_request:
-    branches: [ master ]
+    branches: [ '*' ]
 jobs:
   build-macos:
     runs-on: macos-latest