Revert "Support User#premiumType (#1149)"

This reverts commit 3990957.

Author: abalabahaha

index.d.ts

@@ -2425,7 +2425,6 @@ declare namespace Eris {
     discriminator: string;
     id: string;
     mention: string;
-    premiumType?: 0 | 1 | 2;
     publicFlags?: number;
     staticAvatarURL: string;
     system: boolean;

lib/structures/User.js

@@ -14,7 +14,6 @@ const Endpoints = require("../rest/Endpoints");
 * @prop {String} discriminator The discriminator of the user
 * @prop {String} id The ID of the user
 * @prop {String} mention A string that mentions the user
-* @prop {Number?} premiumType The type of nitro the user has
 * @prop {Number?} publicFlags Publicly visible flags for this user
 * @prop {String} staticAvatarURL The URL of the user's avatar (always a JPG)
 * @prop {Boolean} system Whether the user is an official Discord system user (e.g. urgent messages)
@@ -42,9 +41,6 @@ class User extends Base {
         if(data.discriminator !== undefined) {
             this.discriminator = data.discriminator;
         }
-        if(data.premium_type !== undefined) {
-            this.premiumType = data.premium_type;
-        }
         if(data.public_flags !== undefined) {
             this.publicFlags = data.public_flags;
         }
@@ -139,7 +135,6 @@ class User extends Base {
             "avatar",
             "bot",
             "discriminator",
-            "premiumType",
             "publicFlags",
             "system",
             "username",