websocket_server pip package is out of date and needs to be installed via git

[OscarBarrett]

System Information

• Python version: 3.7
• OS: MacOS 10.14
• Transfer version: master

If websocket_server is installed directly with pip you end up with an older version and the websocket server compains with Client tried to connect but was missing a key when trying to start a transfer.

Instead it should be installed with pip install git+https://github.com/Pithikos/python-websocket-server.