Upgrade langchain to 0.1.0 for pydantic v2 compatibility

requirements.txt

@@ -25,8 +25,8 @@ importlib-metadata==6.7.0
 Jinja2==3.1.2
 jsonschema==4.17.3
 kiwisolver==1.4.4
-langchain==0.0.215
-langchainplus-sdk==0.0.17
+langchain==0.1.0
+langchain-community==0.0.10
 lxml==4.9.2
 Markdown==3.4.3
 markdown-it-py==3.0.0
@@ -40,6 +40,7 @@ more-itertools==9.1.0
 multidict==6.0.4
 mypy-extensions==1.0.0
 networkx==3.1
+numexpr==2.8.4
 numpy==1.25.0
 openai==0.27.8
 openapi-schema-pydantic==1.2.4
@@ -49,7 +50,7 @@ Pillow==9.5.0
 plotly==5.15.0
 protobuf==4.23.3
 pyarrow==12.0.1
-pydantic==1.10.9
+pydantic>=2.0.0
 pydeck==0.8.1b0
 Pygments==2.15.1
 pymdown-extensions==10.0.1

src/backend/chatbot.py

@@ -12,8 +12,8 @@ def _lazy_import_llm_libs():
     global SimpleDirectoryReader, VectorStoreIndex, ServiceContext
     global LlamaCPP, messages_to_prompt, completion_to_prompt
     
-    from langchain.chat_models import ChatOpenAI
-    from langchain.prompts.chat import (
+    from langchain_community.chat_models import ChatOpenAI
+    from langchain_core.prompts.chat import (
         ChatPromptTemplate,
         SystemMessagePromptTemplate,
         AIMessagePromptTemplate,