doc: document and warn if the ICU version is too old

Fixes: https://github.com/nodejs/node/issues/19657

PR-URL: https://github.com/nodejs/node/pull/23766


Reviewed-By: Richard Lau <riclau@uk.ibm.com>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: Refael Ackermann <refack@gmail.com>
Reviewed-By: Ujjwal Sharma <usharma1998@gmail.com>