fix: migrate svelte and vite-plugin-svelte to latest

[paoloricciuti]

We can now use latest for svelte and @sveltejs/vite-plugin-svelte in the migration tool!

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🦋 Changeset detected

Latest commit: 062b804

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 1 package

Name	Type
svelte-migrate	Patch

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[dummdidumm]

There's also some logic in index.js which uses @next which should be switched to @latest

[dominikg]

better not use tags but a fixed "^5.0.0" to avoid breaking it once we release 6.0

[paoloricciuti]

fixed there too