fix(GuildMember): make edit method only modify a copy of the voice state
fix(GuildMember): make edit method only modify a copy of the voice state

This is to fix stale members in voice channels.

appellation/discord.js,Drahcirius/discord.js,SpaceEEC/discord.js,hydrabolt/discord.js,SpaceEEC/discord.js,appellation/discord.js,CodeMan99/discord.js,hydrabolt/discord.js,Lewdcario/discord.js,appellation/discord.js,CodeMan99/discord.js,SpaceEEC/discord.js,hydrabolt/discord.js,Lewdcario/discord.js,Drahcirius/discord.js,CodeMan99/discord.js,Lewdcario/discord.js,Drahcirius/discord.js