Don't invalidate point releases

[jazzsequence]

It turns out that patch releases aren't an issue as far as WP.org validation and the banners that display, so we don't need to validate against patch (x.x.0) releases, we just need to validate minor (x.0) releases.

However, I do like the idea of keeping current functionality as an option. So:

• Update the default behavior to only validate minor (x.0) point releases
  • This is a major-ish change and should be a major version bump to the action
• Allow an optional param to specify the validation behavior (patch x.x.0 vs minor x.0), defaulting to minor.

[jazzsequence]

Resolved in v2 #25