message: Update Heading component
diff: -import React from 'react';
  +/** @jsx jsx */
  import PropTypes from 'prop-types';
  import styled from '@emotion/styled';
  -import { css } from 'emotion';
  +import { css, jsx } from '@emotion/core';
  import HtmlElement from '../HtmlElement';
  import { childrenPropType } from '../../util/shared-prop-types';
  @@ -50,6 +50,7 @@ const HeadingElement = styled(HtmlElement)`
  ${noMarginStyles};
  `;
  +// TODO: refactor this with Emotion 10 as prop
  /**
  * A flexible heading component capable of rendering using any HTML heading tag.
  */
  