add ruby scaffolding to changelog
## Features & Enhancements
+- Implement MVP Ruby-based Scaffolding, initially targeting Rails 5 [\#2142](https://github.com/habitat-sh/habitat/issues/2142)
- Remove `hab pkg exec` calls from Builder Plan hooks [\#2239](https://github.com/habitat-sh/habitat/issues/2239)
- Hard to dynamically calculate version [\#2212](https://github.com/habitat-sh/habitat/issues/2212)
- Run supervisor in the background inside a studio [\#2131](https://github.com/habitat-sh/habitat/issues/2131)
**Merged pull requests:**
+- release 0.22.0 [\#2243](https://github.com/habitat-sh/habitat/pull/2243) ([mwrock](https://github.com/mwrock))
- Clarify pkg\_export error message. [\#2228](https://github.com/habitat-sh/habitat/pull/2228) ([rhass](https://github.com/rhass))
- remove @metadave from maintainers [\#2225](https://github.com/habitat-sh/habitat/pull/2225) ([metadave](https://github.com/metadave))
- sup start and load report status on loaded/started service [\#2222](https://github.com/habitat-sh/habitat/pull/2222) ([mwrock](https://github.com/mwrock))
