`contributors` must be an array, not an object
`contributors` must be an array, not an object

See [the npm
documentation](https://www.npmjs.org/doc/json.html#people-fields-author-contributors)
for this one.

bradparks/js-schema,awei01/js-schema,bradparks/js-schema,molnarg/js-schema,Yerhabe/js-schema,Yerhabe/js-schema,molnarg/js-schema,awei01/js-schema