Modify .NET setup in GitHub Actions workflow

Updated .NET version to 9.0.x in GitHub Actions workflow.

Author: masilver99

.github/workflows/dotnetcore.yml

@@ -7,7 +7,9 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v4
-      - uses: actions/setup-dotnet@v4
+      - name: Setup .NET 9
+        uses: actions/setup-dotnet@v4
         with:
-          dotnet-version: '9.0.9'   # or 7.0.x
+          dotnet-version: '9.0.x'   # or 7.0.x
+      - name: Build
       - run: dotnet build --configuration Release