[APPS-739] - As a ZAT user, I want ZAT to ensure my app targets a valid version of the framework

### Depends on: zendesk/zendesk_apps_support/pull/22

Implements the `zendesk_apps_tools` portion of validating against available framework versions.

Basically throws a warning up when the target version `==` the deprecated version.  This implementation is open for discussion, I have also implemented the warning in `zendesk_apps_support` since it feels better to put the string in a translation and make it available elsewhere.

/cc @zendesk/quokka