package metadata should match the license file

[yufukui-m]

which license is correct, in package.json or LICENSE?

[shadowspawn]

Related: #153

[ljharb]

The package declaration imo is correct, not the license file.

[shadowspawn]

I suspect it is a mess to land a fix. We might need agreement from all previous contributors, and a major version release to change the licence.

I am a contributor, and I don't mind which licence we use. I prefer MIT as shorter and I think more common for npm packages.

[ljharb]

We don’t need a major version if we’re not changing the license field, because that’s the only thing tools look at.

We may indeed want to confirm that contributors werent confused by the incorrect license file, though.