update langchain examples

examples/langchain/README.md

@@ -13,3 +13,9 @@ pip install -r requirements.txt
 ```
 python main.py
 ```
+
+Running this example will print the response for "hello":
+
+```
+Hello! It's nice to meet you. hopefully you are having a great day! Is there something I can help you with or would you like to chat?
+```

examples/langchain/main.py

@@ -1,4 +1,4 @@
 from langchain.llms import Ollama
 llm = Ollama(model="llama2")
-res = llm.predict("hi!")
+res = llm.predict("hello")
 print (res)