[chore] Bump debug to version 4.1.0

[DimitarNestorov]

The kind of change this PR does introduce

• a bug fix
• a new feature
• an update to the documentation
• a code change that improves performance
• other

Current behaviour

New behaviour

Other information (e.g. related issues)

Syncing the version of debug throughout the repositories.
socketio/engine.io#581
socketio/socket.io-client#1304
socketio/socket.io-parser#92
socketio/socket.io-redis-emitter#82
socketio/socket.io-redis-adapter#306

[darrachequesne]

Thanks 👍

[goto-bus-stop]

FWIW this was a breaking change because debug started using arrow functions. I see you've addressed it in socket.io's own tests but all downstream consumers would also have to add transpilation for the debug module to their builds to prevent breakage. (I'm just pinning to socket.io 2.2 for now)