Action name doesn't allow numeric characters

[Adam Israel]

Version affected: Juju 2.0.1

Juju only allows alpha characters in action names, as seen in cmd/juju/action/run.go:

var actionNameRule = regexp.MustCompile("^[a-z](?:[a-z-]*[a-z])?$")

I feel that this is too restrictive, and that the rule should be updated to allow for numeric characters as well.

For example, the utilities 'iperf' and 'iperf3' are distinct applications that may be integrated as an action, but the current name rule prevents that in the latter case.

[Tim Penhey (thumper)]

We have a bunch of actions work being done for the start of 2.3. I expect to get this into that hunk of work, but I'm stopping the punting down the releases as that doesn't help anyone.