doc: add cc oss-security@lists.openwall.com

This commit adds step to CC oss-security@lists.openwall.com as part of
the security release process.

PR-URL: https://github.com/nodejs/node/pull/39191
Refs: https://github.com/nodejs/TSC/issues/1047


Reviewed-By: Beth Griggs <bgriggs@redhat.com>
Reviewed-By: Richard Lau <rlau@redhat.com>
Reviewed-By: Michael Dawson <midawson@redhat.com>