Update requirements.txt

requirements.txt

@@ -1,10 +1,8 @@
-langchain==0.0.284
+langchain==0.0.184
+PyPDF2==3.0.1
 python-dotenv==1.0.0
-streamlit==1.22.0
-unstructured==0.9.2
-tiktoken==0.4.0
+streamlit==1.18.1
+openai==0.27.6
 faiss-cpu==1.7.4
-libmagic==1.0
-python-magic==0.4.27
-python-magic-bin==0.4.14
-OpenAI == 0.28.0
+altair==4
+tiktoken==0.4.0