Run macOS workflows only on opengl-2 branch (#1012)

.github/workflows/macos-ci.yml

@@ -5,6 +5,7 @@ on:
   push:
     branches:
       - main
+      - opengl-2
     tags:
       - 'macos-*'
     paths:
@@ -27,6 +28,7 @@ on:
   pull_request:
     branches:
       - main
+      - opengl-2
     paths:
       - 'platform/ios/**'
       - 'platform/darwin/**'
@@ -131,6 +133,7 @@ jobs:
           ctest -VV --test-dir $BUILD_DIR -R mbgl-test-runner
         env:
           BUILD_DIR: ../../../maplibre-gl-native-macostestbuild
+        if: ${{ github.ref != 'refs/heads/main' }}
 
       - name: Check public symbols
         run: make darwin-check-public-symbols