Update llm.py

Author: willismax

api/llm.py

@@ -20,7 +20,7 @@ class ChatGPT:
 
     def __init__(self):
         self.prompt = Prompt()
-        self.model = os.getenv("OPENAI_MODEL", default="gpt-4o")
+        self.model = os.getenv("OPENAI_MODEL", default="gpt-4o-mini")
         self.temperature = float(os.getenv("OPENAI_TEMPERATURE", default=0))
         self.max_tokens = int(os.getenv("OPENAI_MAX_TOKENS", default=600))