Update IANA timezone db to 2020c

https://mm.icann.org/pipermail/tz-announce/2020-October/000060.html

   Briefly:
     Fiji starts DST later than usual, on 2020-12-20.

   Changes to future timestamps

     Fiji will start DST on 2020-12-20, instead of 2020-11-08 as
     previously predicted.  DST will still end on 2021-01-17.
     (Thanks to Raymond Kumar and Alan Mintz.)  Assume for now that
     the later-than-usual start date is a one-time departure from the
     recent pattern.

Either in JS console in Chrome or v8 should work like these:
const df1 = new Intl.DateTimeFormat("en",{timeZone: "Pacific/Fiji", timeStyle: "long", dateStyle: "long"})
const d3= new Date("2020-12-19T00:00:00.000Z");
const d4= new Date("2020-12-20T00:00:00.000Z");

df1.format(d3)
df1.format(d4)

Before the change:
"December 19, 2020 at 1:00:00 PM GMT+13"
"December 20, 2020 at 1:00:00 PM GMT+13"

After the change:
"December 19, 2020 at 12:00:00 PM GMT+12"
"December 20, 2020 at 1:00:00 PM GMT+13"

TBR=jshin@chromium.org
Bug: 1141065
Change-Id: I4ae2922b1f9ff573c6d04bcaad1223be79e2408f
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/deps/icu/+/2494505
Reviewed-by: Frank Tang <ftang@chromium.org>
Reviewed-on: https://fuchsia-review.googlesource.com/c/third_party/icu/+/449854
Reviewed-by: Fabrice de Gans-Riberi <fdegans@google.com>
10 files changed