Update main.py

main.py

@@ -33,7 +33,7 @@ def root():
      return {"title": "Echo Bot"}
 
 @app.post("/webhook")
-async def callback(request: Request):
+async def webhook(request: Request):
     # get X-Line-Signature header value
     signature = request.headers['X-Line-Signature']
     # get request body as text