support for number backed enums

[stanislav-chetvertkov]

according to
https://stackoverflow.com/questions/66465888/how-to-define-enum-mapping-in-openapi
openapi 3.1 allows the following format for defining number backed enums

openapi: 3.1.0
info:
  title: test
servers:
  - url: /

components:
  schemas:

    Severity:
      type: integer
      oneOf:
        - title: HIGH
          const: 2
          description: An urgent problem
        - title: MEDIUM
          const: 1
        - title: LOW
          const: 0
          description: Can wait forever

it fails with the following error

Error:Unknown type for the following structure (No type definition, class: io.swagger.v3.oas.models.media.JsonSchema, .components.schemas.Severity):
  Tracker(class JsonSchema {
      class Schema {
          type: [integer]
      }
  }, Vector(.components, .schemas, .Severity))

One could generate something similar to this instead

sealed abstract class Severity(val code: Int, val value: String) {
  override def toString: String = value
}
object Severity {
  object members {
    case object HIGH extends Severity(2, "HIGH")
    case object MEDIUM extends Severity(1, "MEDIUM")
    case object LOW extends Severity(0, "LOW")
  }
  val HIGH: Severity  = members.HIGH
  val MEDIUM: Severity = members.MEDIUM
  val LOW: Severity  = members.LOW

  val values  = Vector(HIGH, MEDIUM, LOW)
 
}