fix for gh action branch trigger

Author: ericsink

.github/workflows/dotnet.yml

@@ -2,15 +2,16 @@ name: .NET
 
 on:
   push:
-    branches: [ no-xamarin ]
+    branches: [ main ]
   pull_request:
-    branches: [ master ]
+    branches: [ main ]
 
 jobs:
   build:
 
     strategy:
       matrix:
+        # TODO want Linux here too, but the apple workloads aren't available there.
         os: [windows-2025, macos-15]
 
     runs-on: ${{ matrix.os }}