tag (label) should support revision-based tags

Perforce offers labels that are based on a revision specifier which providers higher-peformance within the perforce system. When performing a release via maven-release-plugin, It would be extremely nice to be able to leverage these types of labels due to their performance benefit.

I'd even be willing to jump in and provide a patch etc, but would need a bit of guidance on how to extend the existing tag command implementation.