Update app.py

Update to new versiom

app.py

@@ -106,7 +106,7 @@ def get_conversation_chain(vectorstore):
 
     """
     llm = HuggingFaceHub(
-        repo_id="mistralai/Mistral-7B-Instruct-v0.1",
+        repo_id="mistralai/Mistral-7B-Instruct-v0.2",
         model_kwargs={"temperature": 0.5, "max_length": 512},
     )
     # llm = ChatOpenAI(temperature=0, model="gpt-3.5-turbo-0613")