Update utils.py

Using text-davinci-002

utils.py

@@ -19,7 +19,7 @@ from langchain.vectorstores.faiss import FAISS
 pickle_file = "open_ai.pkl"
 index_file = "open_ai.index"
 
-gpt_3_5 = OpenAI(model_name='gpt-3.5-turbo',temperature=0)
+gpt_3_5 = OpenAI(model_name='text-davinci-002',temperature=0)
 
 embeddings = OpenAIEmbeddings()