message: Use modern HTML5 <!DOCTYPE>, as discussed in
diff: @@ -24,7 +24,7 @@ class JSDOMEnvironment {
  constructor(config: ProjectConfig): void {
  // lazy require
  - this.document = JSDom.jsdom(/* markup */ undefined, {
  + this.document = JSDom.jsdom('<!DOCTYPE html>', {
  url: config.testURL,
  });
  const global = (this.global = this.document.defaultView);
  