refactor 'inDimension' definition in Metric.json

[zopalmer14]

Updated the inDimension definition to remove references to Dimension as it doesn't exist. The property description and examples in the documentation are a little vague but suggest that a string IRI should work for now.

Note: I will note my additional thoughts/caveats to the PR in a subsequent comment.

DOI DCAT-US 3.0 Documentation: Metric - inDimension

Previous work: GSA/dcat-us3-tools@cb4fb53

Should resolve: #23

[zopalmer14]

Similar to my comment on James's PR for #20, I think there's an opportunity here to leverage the Concept class to address the issue of the missing/unimplemented Dimension (dqv:Dimension) class.

Based on the diagram of DCAT-US Supporting Classes, it appears that Dimension is a subclass of Concept, although the exact implementation of Dimension is not specified either in the diagram itself or the broader documentation, unlike for Role.

That being said, the example for Metric demonstrates that Dimension largely adheres to the Concept schema/definition with the exception of its inCategory property that seems to be an adaptation of Concept's inScheme property. This is further illustrated by the Data Quality Vocabulary (DQV) definition of Dimension that lists it as a subclass of Concept and notes that instances of the class may make use of the property dqv:inCategory.

Consequently, I think that one possible solution/approach would be to replace the invalid $ref to Dimension with one to Concept, although, considering the slight difference between the two, it would probably be better to implement a Dimension.json definition based on the Concept.json definition and the DQV documentation.

[jbrown-xentity]

This looks good to me...