message: Update Heading Component
  Change default heading level to `h2` and include prop type validation for styled-component `as` prop.
diff: @@ -3,7 +3,7 @@ import PropTypes from 'prop-types'
  import {TYPOGRAPHY, COMMON, get} from './constants'
  import theme from './theme'
  -const Heading = styled.h1`
  +const Heading = styled.h2`
  font-weight: ${get('fontWeights.bold')};
  font-size: ${get('fontSizes.5')};
  margin: 0;
  @@ -17,7 +17,8 @@ Heading.defaultProps = {
  Heading.propTypes = {
  ...COMMON.propTypes,
  ...TYPOGRAPHY.propTypes,
  - theme: PropTypes.object
  + theme: PropTypes.object,
  + as: PropTypes.oneOf(['h1', 'h2', 'h3', 'h4', 'h5', 'h6']),
  }
  export default Heading
  