Suggested README Update for Browser Support

[carrvo]

The README mentions that this project

Works with both the browser and node.js.

However the simple use section is only applicable to node.js. As someone fairly new to JavaScript/TypeScript, it would have been nice for there to be a section for use in the browser.

I did eventually figure out that I could successfully use

	<script type="importmap">
	{
	  "imports": {
		"microformats-parser": "https://unpkg.com/microformats-parser@2.0.4/dist/index.mjs",
		"parse5": "https://unpkg.com/parse5@7.1.2/dist/index.js",
		"entities": "https://unpkg.com/entities@6.0.0/dist/esm/index.js",
		"entities/lib/": "https://unpkg.com/entities@6.0.0/dist/esm/"
	  }
	}
	</script>
	<script type="module">
	import { mf2 } from "microformats-parser";
	globalThis.mf2 = mf2;
	</script>

and then proceed with the simple use from there.