Update requirements.txt

requirements.txt

@@ -7,6 +7,7 @@ llama-index==0.10.33
 llama-index-core==0.10.33
 llama-index-embeddings-langchain==0.1.2
 llama-index-embeddings-openai==0.1.9
+llama-index-llms-langchain>=0.1.3
 llama-index-legacy==0.9.48
 llama-index-llms-huggingface==0.1.4
 langchain-core==0.1.46