Update dotnet.yml

Author: JasonXuDeveloper

.github/workflows/dotnet.yml

@@ -132,7 +132,7 @@ jobs:
       - name: Setup .NET
         uses: actions/setup-dotnet@v4
         with:
-          dotnet-version: 6.0.x
+          dotnet-version: 9.0.x
 
       # Restore dependencies
       - name: Restore dependencies