Update app.py with latest changes

app.py

@@ -1,15 +1,17 @@
 import streamlit as st
 import os
 import requests
+from dotenv import load_dotenv  # Only needed if using a .env file
 import re  # To help clean up leading whitespace
 
 # Langchain and HuggingFace
 from langchain_community.vectorstores import Chroma
 from langchain_community.embeddings import HuggingFaceEmbeddings
 from langchain_groq import ChatGroq
-from langchain.chains.qa_with_sources.retrieval import RetrievalQAWithSourcesChain
+from langchain.chains import RetrievalQA
 
 # Load the .env file (if using it)
+load_dotenv()
 groq_api_key = os.getenv("GROQ_API_KEY")
 
 # Load embeddings, model, and vector store