Remove reference to draft-ietf-ntp-cms-for-nts-message
See https://www.ntpsec.org/removal-plan.html
The draft is expired per https://datatracker.ietf.org/doc/draft-ietf-ntp-cms-for-nts-message/
See https://www.ntpsec.org/removal-plan.html
The draft is expired per https://datatracker.ietf.org/doc/draft-ietf-ntp-cms-for-nts-message/