[openapi-types] SchemaObject interface definition dont accept oneOf

[dkMorlok]

For example when i have this schema:

{
	type: 'object',
	properties: {
		ext_id: { // this is ok, defined type
			type: 'string',
			nullable: true,
		},
		visitor_id: { // this is ok, defined $ref
			$ref: '#/components/schemas/def_visitor_id',
		},
		group_id: { // this is not compatible with SchemaObject
			oneOf: [
				{ type: 'null' },
				{ $ref: '#/components/schemas/def_group_id' },
			]
		},
	}
}

and property dont have type or ref then Type definition dont like it :)

[jsdevel]

prs are welcome