timezone data: update to 2018f

Update timezone data to 2018f

http://mm.icann.org/pipermail/tz-announce/2018-October/000051.html

   Volgograd moves from +03 to +04 on 2018-10-28.
   Fiji ends DST 2019-01-13, not 2019-01-20.
   Most of Chile changes DST dates, effective 2019-04-06.

Signed-off-by: Hannu Nyman <hannu.nyman@iki.fi>