Upgrade issue with macOS binary package repository

[Jonathan Perkin <jperkin%pkgsrc.org@localhost>]

As noted to tech-pkg recently I have updated pkg_install to handle newer 
GnuPG key format, as trying to maintain a legacy gnupg20 package from 8 
years ago was proving to be too much hassle, and meant increasingly 
difficult workarounds on my build hosts.

The most recent publish to https://pkgsrc.smartos.org/install-on-macos/ 
uses this patch, along with using the much newer gnupg 2.4.8 for package 
signing, but unfortunately my upgrade testing was not thorough enough 
and if you are using this repository then your next "pkgin upgrade" will 
fail as the existing pkg_install you have installed will be unable to 
read the newer signing key on the incoming pkg_install binary package.

I've provided a workaround here:

  https://federate.me.uk/@jperkin/115547058112719901

which should get you past this, and then subsequent upgrades using the 
new pkg_install will work just fine.

Really sorry for the inconvenience.  In hindsight I should have left a 
large gap between adding support in pkg_install and changing the PGP 
key, though there will always be the possibility that someone will miss 
an in-between update.

--
Jonathan Perkin                    pkgsrc.smartos.org
Open Source Complete Cloud   www.tritondatacenter.com