message: only export default primer props mapper
diff: import map from 'system-classnames/primer'
  -import classnames from 'classnames'
  -const mapWithClassnames = (props, classes) => {
  - const {className, ...mapped} = map(props)
  - const otherClasses = (typeof classes === 'function')
  - ? classes(props)
  - : classes
  - return Object.assign(mapped, {className: otherClasses})
  -}
  -
  -export default mapWithClassnames
  +export default map
  