code: func (b *Bot) SetGroupTitle(chat *Chat, newTitle string) error {
  	params := map[string]string{
  		"chat_id": chat.Recipient(),
  		"title":   newTitle,
  	}
  
  	respJSON, err := b.Raw("setChatTitle", params)
  	if err != nil {
  		return err
  	}
  
  	return extractOkResponse(respJSON)
  }
docs: // SetChatTitle should be used to update group title.