References ACCESS-NRI/model-deployment-template#15

To diff this schema, do diff -- au.org.access-nri/model/spack/environment/deployment/1-0-3.json au.org.access-nri/model/spack/environment/deployment/1-0-4.json since it is a new file.

Background

This PR updates the schema that contains ACCESS-NRI-flavoured restrictions on spack.yaml. The changes are as follows:

• Update spack.specs[] to allow "$ROOT_SPEC" as a valid value
• Update spack.definitions to require definitions for ROOT_PACKAGE/ROOT_SPEC only if spack.specs contains $ROOT_SPEC

Also had some other changes:

• 1-0-3.json: Update $id to be correctly referencing itself
• Updated CHANGELOG.md

Testing

Tested this schema against https://github.com/ACCESS-NRI/ACCESS-OM2/blob/multi-target-spack-yaml-format/spack.yaml, specifically:

• When $ROOT_SPEC exists in spack.specs but ROOT_SPEC/ROOT_PACKAGE doesn't (expected failure)
• When $ROOT_SPEC exists in spack.specs and ROOT_SPEC/ROOT_PACKAGE both exist (expected success)
• When $ROOT_SPEC doesn't exist in spack.specs and ROOT_SPEC/ROOT_PACKAGE doesn't (expected success)
• When $ROOT_SPEC doesn't exist in spack.specs but ROOT_SPEC/ROOT_PACKAGE both exist (expected success)

Can be tested via ajv --strict=true -s au.org.access-nri/model/spack/environment/deployment/1-0-4.json -d ../ACCESS-OM2/spack.yaml