Update dotnet.yml

Author: bugrakosen

.github/workflows/dotnet.yml

@@ -19,7 +19,7 @@ jobs:
       - name: Setup .NET
         uses: actions/setup-dotnet@v1
         with:
-          dotnet-version: 8.0.x
+          dotnet-version: 9.0.x
       - name: Restore Milvasoft.ExpressionBuilder project dependencies
         run: dotnet restore ExpressionBuilder/ExpressionBuilder.csproj
       - name: Build Milvasoft.ExpressionBuilder project