fix(package): missing "type" property in export

[AkaraChen]

Can't get type in TypeScript 5.0.4

This PR add the missing types property to suppress this error.

After:

Same issues in y-websocket: yjs/y-websocket#138

[dmonad]

Thanks!

[sdevil7th]

Hi @dmonad !
I've recently started working with yjs and y-webrtc and I admit it's amazing! Great job!
I'm facing this issue which is blocking my build, I've found some workarounds but they are a bit hacky. Could you please let me know when this fix is coming out? It'd be really helpful.

Thanks!