Update dotnet.yml

Author: pwelter34

.github/workflows/dotnet.yml

@@ -33,7 +33,7 @@ jobs:
       - name: Install .NET
         uses: actions/setup-dotnet@v4
         with:
-          dotnet-version: 8.0.x
+          dotnet-version: 9.x
 
       - name: Restore Dependencies
         run: dotnet restore