Initial support for enum property validations

[bflad]

Closes #18

If the OpenAPI specification declares the enum property and the attribute is determined to be configurable, adds the validator to the specification output.

[bendbennett]

Sweet.
I like the look of this a lot.

[austinvalle]

Awesome! 👍🏻 - Two questions:

• Can/should we implement similar mappings for Float64Attribute and NumberAttribute enum validators?
• Should we write a blurb about this mapping in the DESIGN.md? I've been trying to keep it up-to-date so whenever we create official docs we don't need to dig through the code for these features. Could also just list this in it's own "documentation" issue, instead.

[bflad]

Can/should we implement similar mappings for Float64Attribute and NumberAttribute enum validators?

Probably. 😄 Will update.

EDIT: I'm not sure about NumberAttribute as the representation in OAS and the specification JSON might get funky.

Should we write a blurb about this mapping in the DESIGN.md?

If that makes sense, sure. You'll note though that I'm trying to create a lot of issues to achieve "full" parity where we can. At a certain point it might make more sense to say (or leave as open issues) what's not supported in JSON Schema/OAS. I guess we can cross that bridge when we get there though. I'll update the design doc.

[github-actions]

I'm going to lock this pull request because it has been closed for 30 days ⏳. This helps our maintainers find and focus on the active contributions.
If you have found a problem that seems related to this change, please open a new issue and complete the issue template so we can capture all the details necessary to investigate further.