fix: publish missing files

[bluwy]

Fix #8530

npm and pnpm includes the file in pkg.main to publish by default. Since #8519 removed the pkg.main field, we forgot to add the index.js file to the pkg.files field, causing it to be missing after publish.

This PR updates the pkg.files field

Please don't delete this checklist! Before submitting the PR, please make sure you do the following:

• It's really useful if your PR references an issue where it is discussed ahead of time. In many cases, features are absent for a reason. For large changes, please create an RFC: https://github.com/sveltejs/rfcs
• This message body should clearly illustrate what problems it solves.
• Ideally, include a test that fails without this PR but passes with it.

Tests

• Run the tests with pnpm test and lint the project with pnpm lint and pnpm check

Changesets

• If your PR makes a change that should be noted in one or more packages' changelogs, generate a changeset by running pnpm changeset and following the prompts. Changesets that add features should be minor and those that fix bugs should be patch. Please prefix changeset messages with feat:, fix:, or chore:.

[changeset-bot]

🦋 Changeset detected

Latest commit: b937664

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

This PR includes changesets to release 6 packages

Name	Type
@sveltejs/adapter-cloudflare-workers	Patch
@sveltejs/adapter-netlify	Patch
@sveltejs/adapter-node	Patch
@sveltejs/adapter-static	Patch
@sveltejs/adapter-vercel	Patch
@sveltejs/amp	Patch

Not sure what this means? Click here to learn what changesets are.

Click here if you're a maintainer who wants to add another changeset to this PR

[bluwy]

Looks like we were publishing all files previously: https://www.npmjs.com/package/@sveltejs/adapter-static?activeTab=explore. I scoped this down to the ones we need.

[arackaf]

Holy crap thanks for the fast fix - this is much appreciated! (but not at all expected)