[tz] Chile changes dates for DST from 2019

As of moments ago, the Ministry of Energy in Chile has announced the new schema for DST.

From 2019, Chile will end DST (jump from UTC -3 to UTC -4) on the first sunday of April (2019-04-07T03:00:00Z); and will start DST (from UTC -4 to UTC -3) the first sunday of September (2019-09-08T04:00:00Z)

Also, the Ministry (Susana Jimenez) announced this decision will stick until 2021; and that Magallanes will keep its own time zone (but there will be meetings to talk about this) Announcement in video (in spanish): https://twitter.com/MinEnergia/status/1029000399129374720 -- Juan Correa Poblete PS Labs (http://www.pslabs.cl)