Tochukwu Nwoke

- **Description:** Following a private discussion with @danielchalef, this PR updates the existing rag-conversation-zep template using: - Zep Chathistory class It updates the [rag-conversation-zep](https://github.com/langchain-ai/langchain/blob/master/templates/rag-conversation-zep/rag_conversation_zep/chain.py) chain.py to use the chathistory class...