Currently we don't set a contact email with our accounts. This is an
optional feature, but would be helpful for things like  where we
would be notified of certificates affected by bugs, etc.
Setup the email address in the acme.sh config which will apply with
any new accounts created. To update all the existing hosts, we see if
the account email is added/modified in the config *and* if we have
existing account details; if so we need a manual update call.
For anyone who might be poking here, we also add a note on sharing an
account based on some broadly agreed upon discussion in IRC.