message: Fix validation requests getting 404s
diff: @@ -91,6 +91,9 @@ export default Service.extend({
  let { url, verb } = this._validationRequestParams(record);
  let response = await fetch(url, {
  method: verb,
  + headers: {
  + 'Content-Type': 'application/vnd.api+json'
  + },
  body: JSON.stringify(record.serialize())
  });
  let { status } = response;
  