message: update dom-test-kit readme example
diff: @@ -21,7 +21,7 @@ import { StylableDOMUtil } from '@stylable/dom-test-kit';
  import style from './my-component.st.css';
  const domUtil = new StylableDOMUtil(style);
  -const partElement = domUtil.select(style.part);
  +const partElement = domUtil.select('.part');
  domUtil.hasStyleState(partElement, 'loading');
  ```
  