Using a FreeBSD VM allows building a functioning binary via 'make
podman-release'. This uses Cirrus' freebsd_instance which provisions VMs
on Google Compute Engine.
I attempted to add FreeBSD binaries to the artifacts task but this
failed, apparently because the extra 50Mb of space exceeded a 1Gb limit
in Cirrus.
[NO NEW TESTS NEEDED]
Signed-off-by: Doug Rabson <dfr@rabson.org>