CDN build + global `window` support

Hi 👋

Would it be possible to provide a CDN-ready build (UMD) that exposes the library on `window`?

This would make it easy to use via a simple `<script>` tag without a bundler, e.g.:

```html
<script src="https://cdn.jsdelivr.net/npm/<package-name>/dist/library.min.js"></script>
<script>
  const lib = window.<LibraryName>;
</script>
```

Thanks for considering!
