- Update mail/cone to 0.96
- Update mail/courier-imap to 4.18.0 [1]
- Update mail/maildrop to 2.9.0
- Update mail/sqwebmail to 5.9.0 [1]
- Update security/courier-authlib (and slaves) to 0.68.0 [1]

On request from oliver@, take maintainership of the courier-authlib
ports and the courier-imap port.

Approved by:		oliver@ (maintainer) [1]
Differential Revision:	https://reviews.freebsd.org/D11467