novaclient support to use "X.latest" format in order to talk with the latest nova microversion API, that is very helpful shortcut usage to use new nova side features, we should implement it in OSC.

stack@szxbzci0004 ~/python- openstackclient (master) $ openstack --os-cloud devstack-admin --os-compute- api-version 2.latest server show chenrui_vm
versions supported by client: 2.1 - 2.25