Support native import css/json modules

[josecanciani]

import sheet from './myModule.css' assert { 'type': 'css' };
import sheet from './config.json' assert { 'type': 'json' };

these are valid imports in Chromium/Chrome. It would be nice if we could support, right now the "assert" keyword is an unknown one.

Here's a dynamic import example:

const sheet = (await import('./myModule.css', { assert: { type: 'css' } })).default;

More info: https://v8.dev/features/import-assertions

Thanks!

[Abrifq]

Also adding this:
It's in stage 3.

https://tc39.es/proposal-import-assertions/

[jugglinmike]

Sounds good to me. (As per JSHint's policy on new language features, this became in-scope when the proposal entered "stage 3" of TC39's process, so we're actually lagging behind on this one.)

As always, I'll be happy to help anyone interested in contributing.