Remove support for logging in using username and password
Remove support for logging in using username and password

The Discord devs heavily discourage logging in using username/password (see hammerandchisel/discord-api-docs#69). There is no reason to have it anymore but backwards compatibility - and existing bots can easily be changed to use a token instead.

This heavily backwards-incompatible change also means the next version will be 3.0.0.

Roughsketch/discordrb,Roughsketch/discordrb,meew0/discordrb,megumisonoda/discordrb,VxJasonxV/discordrb,megumisonoda/discordrb,VxJasonxV/discordrb,meew0/discordrb