Обсуждение: pgsql: Sync our copy of the timezone library with IANA release tzcode20

Sync our copy of the timezone library with IANA release tzcode2020d.

There's no functional change at all here, but I'm curious to see
whether this change successfully shuts up Coverity's warning about
a useless strcmp(), which appeared with the previous update.

Discussion: http://mm.icann.org/pipermail/tz/2020-October/029370.html

Branch
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REL9_6_STABLE

Details
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https://git.postgresql.org/pg/commitdiff/58f9f52a3791e760550ac6a32aa085d3ed5ee667

Modified Files
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src/timezone/README |  2 +-
src/timezone/zic.c  | 14 ++++++++++++--
2 files changed, 13 insertions(+), 3 deletions(-)