package/icu: bump version to 73-1
Updated license hash due to copyright year bump:
https://github.com/unicode-org/icu/commit/9e16711b54d055cad10f7dc59f19d124ca6618be
Release notes:
https://icu.unicode.org/download/71
https://icu.unicode.org/download/72
https://icu.unicode.org/download/73
Signed-off-by: Bernd Kuhls <bernd.kuhls@t-online.de>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>