- This should ultimately help for image-to-code back references.
- `org.label-schema.*` labels are now deprecated, in favour of `org.opencontainers.image.*` labels.
  See also: https://github.com/opencontainers/image-spec/blob/master/annotations.md#back-compatibility-with-label-schema
- Git revision (`git rev-parse HEAD`) is now injected at `docker build` time.