build: use main branch for setup-homebrew (#47)

Author: rfay

action.yaml

@@ -49,7 +49,7 @@ inputs:
 runs:
   using: "composite"
   steps:
-    - uses: Homebrew/actions/setup-homebrew@master
+    - uses: Homebrew/actions/setup-homebrew@main
 
     - name: Environment setup
       shell: bash