message: Fix RequestSetup.method interface type
diff: @@ -11,7 +11,7 @@ const INTROSPECTION_QUERY_LENGTH = Buffer.byteLength(INTROSPECTION_QUERY_BODY);
  export interface RequestSetup {
  url: string;
  - method?: 'POST';
  + method?: string;
  headers?: { [key: string]: string };
  }
  