Suggestion: tweak height/spacing/round corners

[BurtHarris]

The stability badge from this set match up well in appearance with others I'm using. For example:

[BurtHarris]

I gather there's a spec for this at https://github.com/badges/shields, it seems like this set doesn't follow the spec.

[BurtHarris]

Perhaps this would be better

![Project Stability: Experimental](https://img.shields.io/badge/stability-Experimental-orange.svg)

[revieweds]

I got it down now I think