Update app.py

app.py

@@ -46,7 +46,7 @@ def respond(
     response_text = ""
     try:
         response = client.chat.completions.create(
-            model="gpt-4o",  # use "gpt-4o-mini" when officially available
+            model="gpt-4o-mini",  # use "gpt-4o-mini" when officially available
             messages=messages,
             max_tokens=max_tokens,
             temperature=temperature,