[Cryptech Core] Impending downtime on bikeshed.cryptech.is

[Rob Austein]

The version of FreeBSD that's running on bikeshed is approaching end
of life.  In theory, upgrading it is just a matter of running the
right freebsd-update command and rebooting, but bikeshed has enough
little customizations (mostly turning off unneeded stuff to reduce the
threat surface) that theory and practice may diverge slightly.

I hope to get to this sometime this week.  If anybody knows of a
reason why there is a particular time that would be bad for this, tell
me, otherwise I'll just do it and notify the list when done.