hen triggered, detect whether the button is touched. If so, output true, otherwise, false.
pin: int. The gpio pin which is attached by the button
trigger: any type. It is a trigger signal, and whenever it comes, the service will check whether touched.
bool: boolean. true means it is touched, otherwise, false.
It will check whether button is touched in every 1s, if it is touched, the buzzer starts buzzing, otherwise, the buzzer stop buzzing.