Migrate from svelte-kit package to @sveltejs/package

[ZerdoX-x]

Related Issues

https://github.com/Splidejs/svelte-splide/issues/12

Description

See https://github.com/sveltejs/kit/pull/8922 for the information about required updates.

What I did in the PR:

1. npm i -D @sveltejs/package
2. npx svelte-migrate package

Not sure, but maybe additional changes can be made to this PR.. I have never worked on publishing svelte packages and actually any types of packages. What I think is that maybe .npmignore can be added, which would list files which are not needed for a package to work, at least .github folder? What do you think?

[ymongo]

@NaotoshiFujita is it good to merge? 👍