chore: move migrate package to this repository

[benmccann]

see also https://github.com/sveltejs/kit/pull/12971

[changeset-bot[bot]]

🦋 Changeset detected

Latest commit: f3e865a5968a36aa14a44fa82c905db63a0c0272

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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[pkg-pr-new[bot]]

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pnpm add https://pkg.pr.new/sveltejs/cli/sv@274

pnpm add https://pkg.pr.new/sveltejs/cli/svelte-migrate@274

commit: f3e865a