TextBasedChannel#lastMessage is now a getter (#59)
TextBasedChannel#lastMessage is now a getter (#59)

Also adding TextBasedChannel#lastMessageChannelID

Commit: https://github.com/discordjs/discord.js/commit/630009f3cf6185f9b94ec146dd1a2f0bdf7f9acc
acdenisSK/discord.js-typings