CHANGES WITH 14:
* Schema validation: The osbuild python library gained support for
retrieving the metadata of modules and schema validation. This is
being used on each invocation of osbuild in order to validate the
manifest. Should the validation fail the build is aborted and
validation errors are returned, either in human readable form or
in JSON, if `--json` was specified.
* A `--inspect` command line option was added for osbuild. Instead
of attempting to build the pipeline, the manifest will be printed
to stdout in JSON form, including all the calulcated identifiers
of stages, the assembler and the `tree_id` and `output_id` of the
pipeline (and build pipelines). Schema validation will be done and
errors will be reported.
* Internally, the buildroot class now uses `PYTHONPATH` to point to
the `osbuild` module instead of the symlinks or bind-mounts in the
individual modules.
* Fixes to the CI and many cleanups to the schemata, sample and test
pipelines as a result of the schema validation work.
Contributions from: Christian Kellner, David Rheinsberg, Ondřej Budai
- Berlin, 2020-05-06