Add a note to script about which websocket library is used.

script_examples/websockets_api_example.py

 #This is an example that uses the websockets api to know when a prompt execution is done
 #Once the prompt execution is done it downloads the images using the /history endpoint
 
-import websocket
+import websocket #NOTE: websocket-client (https://github.com/websocket-client/websocket-client)
 import uuid
 import json
 import urllib.request