Fix chat-with-history.py example (#337)

Fix chat-with-history.py example

---------

Co-authored-by: Parth Sareen <parth.sareen@ollama.com>

examples/chat-with-history.py

@@ -31,8 +31,8 @@ while True:
   )
 
   # Add the response to the messages to maintain the history
-  messages.append(
+  messages += [
     {'role': 'user', 'content': user_input},
     {'role': 'assistant', 'content': response.message.content},
-  )
+  ]
   print(response.message.content + '\n')