Update requirements.txt

requirements.txt

@@ -1,13 +1,15 @@
-streamlit==1.23.1
-langchain==0.0.225
-pydantic==1.9
 utils==1.0.1
 cohere==4.11.2
-openai==0.27.8
 pypdf2==3.0.1
-tiktoken==0.4.0
 PyPDF2==3.0.1
-chromadb==0.3.27
-google-search-results==2.4.2
 fpdf==1.7.2
-pypdf==3.12.1
+pypdf==3.12.1
+streamlit~=1.23.1
+utils~=1.0.1
+cohere~=4.11.2
+openai~=0.27.8
+tiktoken~=0.4.0
+langchain~=0.0.230
+chromadb~=0.3.27
+google-search-results~=2.4.2
+duckduckgo-search