[spec] framework .NET 9 set

Author: i4004

.github/workflows/build.yml

@@ -15,7 +15,7 @@ jobs:
         os: [ubuntu-latest, windows-latest]
         include:
           - os: ubuntu-latest
-            test-framework-command: --framework net8.0
+            test-framework-command: --framework net9.0
 
     steps:
       - name: Code Checkout