Use proper exports field in package.json to be truly ESM compatible package

[RIP21]

Is your feature request related to a problem? Please describe.
In ESM you cannot import from the directory of the package. You can only import files described in exports mapping.

Describe the solution you'd like
Adding exports to package.json like that

  "exports": {
    ".": {
      "types": "./dist/index.d.ts",
      "import": "./dist/index.es.js",
      "require: "./dist/index.js",
      "default": "./dist/index.es.js"
    },
    "./dist/LiteYouTubeEmbed.css": "./dist/LiteYouTubeEmbed.css"
  },

Should likely do the trick.

More on that here https://nodejs.org/api/packages.html#conditional-exports

Describe alternatives you've considered
No alternatives. It's standard