Disable FreeBSD 12 builds on Cirrus CI.
Disable FreeBSD 12 builds on Cirrus CI.

Build have begin failing with this error:

ld-elf.so.1: /usr/local/bin/rsync: Undefined symbol "locale_charset"

There does not appear to be a new version so hopefully this is a transient error (hoping the same for FreeBSD 13, see bb11539a). Disable for now to free the build pipeline.

pgbackrest/pgbackrest,pgbackrest/pgbackrest,pgbackrest/pgbackrest