Update app.py

app.py

@@ -43,7 +43,7 @@ vectorstore = Chroma.from_documents(docs, embedding=OpenAIEmbeddings(), persist_
 vectorstore.persist()
 
 chain = ConversationalRetrievalChain.from_llm(
-    ChatOpenAI(temperature=0.1, model_name='gpt-3.5-turbo'),
+    ChatOpenAI(temperature=0.1, model_name='gpt-4.5'),
     retriever=vectorstore.as_retriever(search_kwargs={'k': 6}),
     return_source_documents=True,
     verbose=False