I'll get in touch with the upstream maintainers for this. Hopefully for the next release, it will be adopted.
Hm, try it, but I don't think they will...
They will probably just tell you that it's a bug in your tools (rug, rpm, whatever you're using)
Note, you can do this on your own. Nobody forces you to use the same version numbering scheme as upstream. (You should follow the upstream scheme for released versions, but I think that deviating from it for unreleased versions is legitimate.)
Would 0.2.0 be treated newer as 0.2rc2?
You might be interested in these scripts: