pgsql: Update time zone data files to tzdata release 2023c.

Update time zone data files to tzdata release 2023c.

DST law changes in Egypt, Greenland, Morocco, and Palestine.

When observing Moscow time, Europe/Kirov and Europe/Volgograd now
use the abbreviations MSK/MSD instead of numeric abbreviations,
for consistency with other timezones observing Moscow time.

Also, America/Yellowknife is no longer distinct from America/Edmonton;
this affects some pre-1948 timestamps in that area.

Branch
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REL_15_STABLE

Details
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https://git.postgresql.org/pg/commitdiff/62b22caa5531da8f6498f09f15ac0f09c95b1459

Modified Files
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src/timezone/data/tzdata.zi | 132 ++++++++++++++++++++++++++++++++---------
src/timezone/known_abbrevs.txt | 3 +-
2 files changed, 106 insertions(+), 29 deletions(-)