Fix the demo

[simonw]

https://datasette-render-images-demo.datasette.io/favicons/favicons.json?_shape=array&_size=1 Is broken

Should be able to deploy it again using modern Vercel.

[simonw]

Here's the old favicons.db database from the demo: https://static.simonwillison.net/static/2020/datasette-render-images-favicons.db

[simonw]

{
  "source": "datasette-render-images",
  "source_url": "https://github.com/simonw/datasette-render-images",
  "title": "datasette-render-images demo"
}

[simonw]

I can imitate this: https://github.com/simonw/datasette-json-html/blob/b00b998f53e9121f6c8320808be7bf8f426d8be9/.github/workflows/deploy-demo.yml#L73