pgsql: Implement unaccent Unicode data update in meson

Implement unaccent Unicode data update in meson

The meson/ninja update-unicode target did not cover the required
updates in contrib/unaccent/.  This is fixed now.

Reviewed-by: Chao Li <li.evan.chao@gmail.com>
Reviewed-by: Alexander Borisov <lex.borisov@gmail.com>
Discussion: https://www.postgresql.org/message-id/flat/2a668979-ed92-49a3-abf9-a3ec2d460ec2%40eisentraut.org

Branch
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master

Details
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https://git.postgresql.org/pg/commitdiff/1b0c269f2e4f1cdcfd6d7c71d8eaa8020c23ebdb

Modified Files
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contrib/unaccent/meson.build   | 41 ++++++++++++++++++++++++++++++++++++++++-
meson.build                    |  5 +++++
src/common/unicode/README      |  2 +-
src/common/unicode/meson.build | 29 +++++++++++++++--------------
4 files changed, 61 insertions(+), 16 deletions(-)