BM8563 wakeup from time

[RobinsonLaw]

I have test the following cannot wakeup from specific time

    wakeuptime.hour = 10;
    wakeuptime.min = 34;
    wakeuptime.sec = 00;
    M5.shutdown(wakeuptime);

[estshorter]

A fix similar to this pull request may be helpful.

[cat-in-136]

The following workaround works without changing the M5EPD library. Same as M5.RTC.setAlarmIRQ()

M5.shutdown(RTC_Date(-1, -1, -1, -1), wakeuptime);

Other notes:

• Execute M5.RTC.begin() in advance
• Pull the USB type-C cable from M5Paper, i.e, do not charge power.
• Use M5.shutdown() (or M5.disableMainPower()), not deep sleep. See also: https://community.m5stack.com/topic/2892/m5paper-shutdown-deep-sleep-wakeup

[TinyuZhao]

RTC wake-up timer can only be accurate to the day, hour and minute, but not to the second.