Update app.py

app.py

@@ -104,7 +104,7 @@ async def on_thread_create(thread):
 
 def post_to_slack_forum_version(channel, text, author, thread_ts=None):
     print("6")
-    text = author + ": " + text
+    text = f"{author}" + ": " + text
     try:
         response = slack_client.chat_postMessage(
             channel=channel,