Comment 1 for bug 1891418

The actual explanation is under the help of `juju deploy` so the only missing part is a direction to the help from the error message I suppose.

> An 'application name' provides an alternate name for the application. It works
> only for charms; it is silently ignored for bundles (although the same can be
> done at the bundle file level). Such a name must consist only of lower-case
> letters (a-z), numbers (0-9), and single hyphens (-). The name must begin with
> a letter and not have a group of all numbers follow a hyphen:
>
> Valid: myappname, custom-app, app2-scat-23skidoo
> Invalid: myAppName, custom--app, app2-scat-23, areacode-555-info