Nested Discriminator support

Hey Readme.io community

I would like to know how I can achieve nested discriminator oneOf -> oneOf nested.

When I have a nested oneOf property it does not take first discriminator for "channel"

Example Code

"oneOf": [
  {
    "$ref": "#/components/schemas/TemplateSMSPostRequestDto"
  },
  {
    "$ref": "#/components/schemas/TemplateViberPostRequestDto"
  }
],
"discriminator": {
  "propertyName": "channel",
  "mapping": {
    "SMS": "#/components/schemas/TemplateSMSPostRequestDto",
    "VIBER": "#/components/schemas/TemplateViberPostRequestDto"
  }
}

TemplateSMSPostRequestDto

{
  "title": "SMS Template",
  "type": "object",
  "required": [
    "text",
    "channel"
  ],
  "properties": {
    "channel": {
      "type": "string"
    },
    "text": {
      "type": "string",
      "maxLength": 1000
    }
  }
}

TemplateViberPostRequestDto

{
  "title": "Viber Template",
  "type": "object",
  "allOf": [
    {
      "required": [
        "channel"
      ],
      "properties": {
        "channel": {
          "type": "string"
        }
      }
    },
    {
      "oneOf": [
        {
          "$ref": "#/components/schemas/TemplateViberImagePostRequestDto"
        },
        {
          "$ref": "#/components/schemas/TemplateViberDocumentPostRequestDto"
        }
      ],
      "discriminator": {
        "propertyName": "type",
        "mapping": {
          "image": "#/components/schemas/TemplateViberImagePostRequestDto",
          "document": "#/components/schemas/TemplateViberDocumentPostRequestDto"
        }
      }
    }
  ]
}

TemplateViberImagePostRequestDto

{
  "title": "Image Template",
  "type": "object",
  "required": [
    "type",
    "channel"
  ],
  "properties": {
    "type": {
      "type": "string"
    },
    "text": {
      "type": "string"
    },
    "url": {
      "type": "string",
      "description": "One of 'url' or 'media_id' is required"
    },
    "media_id": {
      "type": "string",
      "format": "uuid",
      "description": "One of 'url' or 'media_id' is required"
    }
  }
}

TemplateViberDocumentPostRequestDto

{
  "title": "Document Template",
  "type": "object",
  "required": [
    "type",
    "filename",
    "channel"
  ],
  "properties": {
    "type": {
      "type": "string"
    },
    "filename": {
      "type": "string"
    },
    "url": {
      "type": "string"
    },
    "media_id": {
      "type": "string",
      "format": "uuid"
    }
  }
}