Update building.yaml to add roof class

[atiannicelli]

Category

What kind of change is this?
Please select one of the following four options.
Consult Pull request merging criteria for a description of each category.

1. Cosmetic change.
2. Documentation change by member.
3. Documentation change by Overture tech writer.
4. Material change.

Description

This adds "roof" to the possible building class list

Reference

https://github.com/OvertureMaps/tf-buildings/issues/183

Testing

No extensive testing was performed. It is my belief that adding just one value to the class list should not cause issues.

Checklist

1. Add relevant examples.
2. Add relevant counterexamples.
3. Update any counterexamples that became obsolete. For example, if a counterexample uses property A but is not intended to test property A's validity, and you made a schema change that invalidates property A in that counterexample, fix the counterexample to align it with your schema change.
4. Update in-schema documentation using plain English written in complete sentences, if an update is required.
5. Update Docusaurus documentation, if an update is required.
6. Review change with Overture technical writer to ensure any advanced documentation needs will be taken care of, unless the change is trivial and would not affect the documentation.

Documentation Website

Update the hyperlink below to put the pull request number in.

[Docs preview for this PR.](https://dfhx9f55j8eg5.cloudfront.net/pr/<PUT THE PR # HERE>)

[vcschapp]

As agreed in today's Schema TF meeting (2024-10-16), relaxing validation on a top-level property (e.g. adding enum member) will be classified as "non-breaking" for the time being. So this PR is now a "non-breaking" change and we can merge it. We'll still have to finalize the rest of the process around versioning and stability, but we might as well be pragmatic and merge the stuff that is known to be on the "non-breaking" side.