Merge pull request #747 from DarkGuy10/patch-1

fix(typings): add strict `type` prop to `PartialGroupDMChannel`

typings/index.d.ts

@@ -2571,6 +2571,7 @@ export class PartialGroupDMChannel extends TextBasedChannelMixin(Channel, [
   'setNSFW',
 ]) {
   private constructor(client: Client, data: RawPartialGroupDMChannelData);
+  public type: 'GROUP_DM';
   public name: string | null;
   public icon: string | null;
   public readonly recipients: Collection<Snowflake, User>;