Parameterize buf compatibility target
Parameterize buf compatibility target

Parameterize it so we can arbitrary target other versions, if we
are doing some manual checking, specially in the beginning when we may
want to validate compatibilities for skip release upgrades.

Also, introduce `checkbuf` target so we can run buf linter without the
rest.

use beta

dvusboy/nomad,dvusboy/nomad,dvusboy/nomad,burdandrei/nomad,burdandrei/nomad,burdandrei/nomad,hashicorp/nomad,burdandrei/nomad,dvusboy/nomad,burdandrei/nomad,dvusboy/nomad,burdandrei/nomad,hashicorp/nomad,hashicorp/nomad,hashicorp/nomad,hashicorp/nomad,hashicorp/nomad,dvusboy/nomad,dvusboy/nomad,burdandrei/nomad