message: Fixed IE demo
diff: import 'core-js';
  +import { useState } from 'react';
  import ReactDOM from 'react-dom';
  import QueryBuilder, { defaultValidator, Field, RuleGroupType, RuleType } from '../src';
  import './styles/ie11.scss';
  -export const validator = (r: RuleType) => !!r.value;
  +const validator = (r: RuleType) => !!r.value;
  const fields: Field[] = [
  { name: 'firstName', label: 'First Name', placeholder: 'Enter first name', validator },
  @@ -87,10 +88,14 @@ const initialQuery: RuleGroupType = {
  not: false
  };
  -const IE11Test = () => (
  +const IE11Test = () => {
  + const [query, setQuery] = useState(initialQuery);
  +
  + return (
  <QueryBuilder
  fields={fields}
  - query={initialQuery}
  + query={query}
  + onQueryChange={(q) => setQuery(q)}
  addRuleToNewGroups
  enableDragAndDrop
  showCloneButtons
  @@ -98,5 +103,6 @@ const IE11Test = () => (
  validator={defaultValidator}
  />
  );
  +};
  ReactDOM.render(<IE11Test />, document.getElementById('ie11'));
  