Descriptor format changes
- `openshift` key was removed, use newly added `user` instead
- `hash` was renamed to `md5sum`
Other changes
`--scripts` CLI parameter was renamed to `--scripts-url`
Enhancements
- Support for CCT: https://github.com/containers-tools/cct
- Default user is now `root`
- Added schema validation using kwalify
- Extended tests
- Support for runtime changes with CCT, 26
- A bit more documentation, see https://github.com/jboss-dockerfiles/dogen/tree/master/docs