message: Fixes propType validation for justifyContent
diff: import React from 'react';
  import PropTypes from 'prop-types';
  import styled from 'styled-components';
  +import { space, justifyContent, alignItems } from 'styled-system';
  +
  import { pick, omit } from 'underscore';
  import compactObject from 'react/util/compactObject';
  @@ -40,9 +42,9 @@ const BorderedBox = ({
  BorderedBox.propTypes = {
  children: PropTypes.node.isRequired,
  - ...INNER_PROPS_KEYS.reduce((memo, key) => (
  - { ...memo, [key]: PropTypes.number }
  - ), {}),
  + ...space.propTypes,
  + ...alignItems.propTypes,
  + ...justifyContent.propTypes,
  };
  BorderedBox.defaultProps = {
  