deps: update ICU to 68.1

Refs: https://github.com/unicode-org/icu/releases/tag/release-68-1

PR-URL: https://github.com/nodejs/node/pull/36187


Reviewed-By: Richard Lau <rlau@redhat.com>
Reviewed-By: Gireesh Punathil <gpunathi@in.ibm.com>
Reviewed-By: Michael Dawson <midawson@redhat.com>
Reviewed-By: Rich Trott <rtrott@gmail.com>
Reviewed-By: Jiawen Geng <technicalcute@gmail.com>