Update requirements.txt

requirements.txt

@@ -1,5 +1,9 @@
-langchain==0.1.10
-google-generativeai==0.4.0
-gradio==4.34.0
-faiss-cpu==1.7.4
-pypdf==3.17.1
+gradio>=4.0.0
+google-generativeai>=0.3.0
+langchain-google-genai>=0.0.1
+langchain>=0.0.267
+langchain-community>=0.0.13
+faiss-cpu>=1.7.4
+pypdf>=3.15.1
+pytz>=2023.3
+python-dotenv>=1.0.0