proper enum schema for pydantic

[jbkoh]

Summary

Checklist

• [x] If code changes were made then they have been tested.
  • [x] I have updated the documentation to reflect the changes.
• [x] This PR fixes an issue.
• [x] This PR adds something new (e.g. new method or parameters).
  • [x] This change has an associated test.
• [x] This PR is a breaking change (e.g. methods or parameters removed/renamed)
  • It might be breaking anybody using int instead of Enum when using pydantic, though I don't think that's desired.
• [ ] This PR is not a code change (e.g. documentation, README, ...)

[jbkoh]

just added a test too.

[jbkoh]

@Gobot1234 please review and let me know if it's in the right direction.