Update tutorial-serverless-notification.md

set python to model v1

Author: JialinXin

articles/azure-web-pubsub/tutorial-serverless-notification.md

@@ -105,7 +105,7 @@ In this tutorial, you learn how to:
 
     # [Python](#tab/python)
     ```bash
-    func init --worker-runtime python
+    func init --worker-runtime python --model V1
     ```
 
 2. Follow the steps to install `Microsoft.Azure.WebJobs.Extensions.WebPubSub`.