chore: protocol version 5
chore: protocol version 5

There are two differences with the 4th version:

- a CONNECT packet can now contain a payload (for authentication purposes)
- the underlying Engine.IO protocol has been updated

Reference: https://github.com/socketio/engine.io-protocol#difference-between-v3-and-v4

socketio/socket.io-parser,socketio/socket.io-parser,Automattic/socket.io-parser,socketio/socket.io-parser