deps: update ICU to 68.2

Refs: https://github.com/unicode-org/icu/releases/tag/release-68-2

PR-URL: https://github.com/nodejs/node/pull/36980


Reviewed-By: Antoine du Hamel <duhamelantoine1995@gmail.com>
Reviewed-By: Richard Lau <rlau@redhat.com>
Reviewed-By: Benjamin Gruenbaum <benjamingr@gmail.com>
Reviewed-By: Beth Griggs <bgriggs@redhat.com>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>