Use dotnet 9 for macos github action runner.

.github/workflows/macos.yml

@@ -20,7 +20,7 @@ jobs:
         submodules: true
     - uses: actions/setup-dotnet@v4
       with:
-        dotnet-version: '8.x'
+        dotnet-version: '9.x'
     - name: Install dotnet workload 
       run: dotnet workload install maui maccatalyst
     - name: Build Emgu CV native binary