Completed work reflecting schema version in XSD and JSON schema (#57)

[wendellpiez]

Committer Notes

Completing Issue #57 by adding version info to XSD and JSON Schema (but see comments for any unresolved questions).

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[wendellpiez]

Current status:

• New element schema-version is permitted (not required) at the top level of a metaschema
• The metaschema Schematron checks for this value and issues a warning if it is not given (non-ws) - with current settings this is a blocking error even if XSD validation passes
• In schema generation, it maps to a representation of the version in the XSD and JSON schemas as specified above (by a xs:schema/@version attribute or $id property)
• Using this element, all the metaschemas (and hence all schemas) now also show <schema-version>1.0-M1</schema-version> (and validate with no warnings from Metaschema Schematron)
• The metadata module declares element oscal-version for any metaschema that uses its metadata model; its value is still unconstrained
• All the sample data (catalogs and profiles) show <oscal-version>1.0-M1</oscal-version> in their metadata

We could add a static or dynamic check for the value of oscal-version, in OSCAL instances, into a Schematron (cf #400 for gathering Schematron requirements).

We could also tighten the requirements by removing the test from the Metaschema Schematron and making the schema-version element required in the Metaschema XSD. The main question there is, is it an error if no version is given in a metaschema module that is never used for a schema directly, but only by calling from other modules. Without further qualification, a dummy value (i.e. <schema-version/>) would be XSD valid (one reason I opted for Schematron-only checking at present).

[david-waltermire]

LGTM