Support the valid 2 ways to reference a license file and 2 different licenses

[watilde]

The following json line is the valid way to reference a file as a license file.

{ "license" : "SEE LICENSE IN <filename>" }

Also, there is a way to write 2 different kind of license:

{ "license" : "(ISC OR GPL-3.0)" }

The rest of ToDo

• [x] AND
• [x] OR
• [ ] WITH
• [ ] PLUS
• [ ] SEE LICENSE IN

Could you support both style?

refs: https://docs.npmjs.com/files/package.json#license

[twada]

@watilde Nice feature request!