use props in package code example

Example 1: react props.children proptype

import PropTypes from 'prop-types'

...

static propTypes = {
    children: PropTypes.oneOfType([
        PropTypes.arrayOf(PropTypes.node),
        PropTypes.node
    ]).isRequired
}

Example 2: how to make proptypes either or

size: PropTypes.oneOfType([
  PropTypes.string,
  PropTypes.number
]),