Missing websockets dependency

[nSedrickm]

Sync API fails to start after running the command:

python3 gateway_server/sessions_websocket.py

Here is the error

Traceback (most recent call last):
  File "gateway_server/sessions_websocket.py", line 6, in <module>
    import websockets
ModuleNotFoundError: No module named 'websockets'

[sherlockwisdom]

Fixed