Fix release.yml Test step by adding explicit framework flags

Co-authored-by: PhenX <42170+PhenX@users.noreply.github.com>

Author: Copilot

.github/workflows/release.yml

@@ -41,8 +41,11 @@ jobs:
       - name: Build
         run: dotnet build --configuration Release --no-restore /p:Version=$VERSION
 
-      - name: Test
-        run: dotnet test --configuration Release --no-restore --no-build --verbosity normal
+      - name: Test net8.0
+        run: dotnet test --configuration Release --no-restore --no-build --verbosity normal --framework net8.0
+
+      - name: Test net9.0
+        run: dotnet test --configuration Release --no-restore --no-build --verbosity normal --framework net9.0
 
       - name: Pack nuget packages
         run: dotnet pack --configuration Release --no-restore --no-build --output nupkgs /p:PackageVersion=$VERSION