Listing an array of authors in package.json breaks some tools that parse it

[ikaronen-relex]

Hi! While upgrading some dependencies in our project, I noticed an issue with the metadata for this package that caused our build process to crash after the upgrade.

Specifically, according to the npm documentation the author field in package.json should designate a single person and be either a JSON object or a string. This package currently has "author": ["nkbt", "chenglou"], which violates the spec and crashes some tools that try to parse it according to the spec (such as https://github.com/pivotal/LicenseFinder). While such tools should probably be made more robust, the current package.json for this project is (AFAICT) still invalid.

Probably the simplest fix would be to change the key from "author" to "contributors", which has the same semantics but allows multiple values. It could also be a good idea to validate the package.json against https://www.npmjs.com/package/package.json-schema.