Document that running `./tools/release.sh` script using the recently
added `-a` CLI flag enables the previously-default interactive interface
to select the correct PGP key.
PR-URL: https://github.com/nodejs/node/pull/56124
Reviewed-By: Rafael Gonzaga <rafael.nunu@hotmail.com>
Reviewed-By: Antoine du Hamel <duhamelantoine1995@gmail.com>
Reviewed-By: Richard Lau <rlau@redhat.com>