0.8.4

A small release, but pretty important since it fixes the new Nitro discriminator feature not updating properly.

Additions:

• Added the webhooksUpdate event (b480a8b)

Fixes:

• Fixed Nitro discriminators not updating properly (8e11525)
• Fixed custom invalid usage messages in CommandClient (baf1700)
• Fixed some undefined properties in the guildUpdate event (83bad4a)