Add Tailwind styling support

[Lucasmm016]

Add support for Tailwind styling through className, example:

const t = () => toast.success('Success!', {
     className: 'bg-indigo-500'
   })

Reason: Makes it easier for those who use the lib in Next 13!

[emilkowalski]

This is already added.

[Lucasmm016]

And how do I style toast with tailwind? I'm using it with Next 13.

[emilkowalski]

https://sonner.emilkowal.ski/toast#headless

or just className like here https://sonner.emilkowal.ski/toast#rendering-the-toast