Updates whether an app is an administrator of the chat. An app holds a role exactly as a user does, so a bot administers a chat on the same terms, and role is the only field an app has to update: it carries no read position, favourite flag or inbox state. role is required and the app must already be a member. Returns the updated member, always with an @type of app, since the variant follows the member updated rather than the caller. Supplying the role it already holds is a no-op that returns it unchanged.