certbot 5.x renamed the field in `certbot certificates` output
from "Domains:" to "Identifiers:". The "Check if domains have
changed" task greps that output for "Domains" to read a
certificate's current domains. On certbot 5.x the grep matches
nothing, so letsencrypt_cert_domains becomes empty,
letsencrypt_cert_domains_changed is always true, and every
certificate is reissued on every run.
Match both the old "Domains" and new "Identifiers" labels in
create-cert-standalone.yml and create-cert-webroot.yml so the
check works on certbot 4.x and 5.x alike.
