message: update prop type to node
diff: @@ -104,7 +104,7 @@ UnderlineNav.Link.defaultProps = {
  }
  UnderlineNav.Link.propTypes = {
  - as: PropTypes.oneOfType([PropTypes.string, PropTypes.func]),
  + as: PropTypes.node,
  href: PropTypes.string,
  selected: PropTypes.bool,
  ...COMMON.propTypes
  