Use NET 9 in the publish pipeline

Author: Adrian Alzate

.github/workflows/publish-package.yml

@@ -16,7 +16,7 @@ jobs:
       - uses: actions/checkout@v3
       - uses: actions/setup-dotnet@v2
         with:
-          dotnet-version: 6.0.x
+          dotnet-version: 9.0.x
       - name: Build
         run: dotnet build --configuration Release
       - name: Run unit tests