pkgbase major version upgrades

Someone might like to update <https://wiki.freebsd.org/PkgBase#major>, 
where the current example is 11 to 12.

:x86:64 was recently a cause of confusion for someone (not me); and so on.

Ideally, verify the validity of the updated section with:

- a pkgbase upgrade from 14.1 to 14.2, followed by 14.2 to 15.0-CURRENT

– including attention to non-root user account passwords and group 
memberships that exist in the 14.1 environment.

Thanks