message: change Button is prop type
diff: @@ -33,7 +33,7 @@ Button.propTypes = {
  children: PropTypes.node,
  disabled: PropTypes.bool,
  grouped: PropTypes.bool,
  - is: PropTypes.oneOf(['button', 'a', 'summary']),
  + is: PropTypes.oneOfType([PropTypes.oneOf(['button', 'a', 'summary', 'input']), PropTypes.func]),
  linkStyle: PropTypes.bool,
  onClick: PropTypes.func,
  scheme: PropTypes.string,
  