[tz] North Korea timezone to become GMT+9 from May 5 2018

[Michael H Deckers]

   On 2018-04-30 09:07, Magnus Danielson quoted a Korean decree:

> Secondly, the reset Pyongyang time shall be applied from May 5, Juche
> 107 (2018).

    This can be read to imply that the switch is from 23:30 to 00:00,
    so that the new time scale is applied from 2018-05-05 onwards.
    The proposed patch would have the switch 30 minutes later.

    Michael Deckers.