clarify rhel/centos and beta1
clarify rhel/centos and beta1

Specify RHEL7, RHEL8, CentOS7, CentOS8
Specify beta1 for 0.10 (beta2 coming soon? :wink: )
burdandrei/nomad,hashicorp/nomad,hashicorp/nomad,burdandrei/nomad,hashicorp/nomad,dvusboy/nomad,dvusboy/nomad,dvusboy/nomad,dvusboy/nomad,burdandrei/nomad,dvusboy/nomad,hashicorp/nomad,burdandrei/nomad,dvusboy/nomad,hashicorp/nomad,hashicorp/nomad,burdandrei/nomad,burdandrei/nomad,burdandrei/nomad,dvusboy/nomad