Svelte CodeSandbox demo doesn't compile

[Dman757]

Describe the bug

Demo on the felte.dev website (and the github readme.md):
https://codesandbox.io/s/felte-v1-demo-svelte-0egr6?from-embed

felte/README.md

Line 18 in 9e889fb

Felte is a simple to use form library for Svelte, Solid and React. No `Field` or `Form` components are needed, just plain stores and actions to build your form however you like. You can see it in action in this [CodeSandbox demo](https://codesandbox.io/s/felte-demo-wce2h?file=/App.svelte)!

Which package/s are you using?

felte (Svelte)

Environment

• OS: N/A
• Browser: Chrome
• Version: N/A

To reproduce

No response

Small reproduction example

https://codesandbox.io/s/felte-v1-demo-svelte-0egr6?from-embed

Screenshots

Additional context

No response