[chore] update vite-plugin-svelte

[bluwy]

Fixes #720

May address #2612 if experimental.prebundleSvelteLibraries works. I've tested this in a local production repo and it's working flawlessly.

vite-plugin-svelte also dropped support for node 12.

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🦋 Changeset detected

Latest commit: df0fc7b

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

This PR includes changesets to release 1 package

Name	Type
@sveltejs/kit	Patch

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[ignatiusmb]

We might need to update Svelte core as well for the new enableSourcemap option

[bluwy]

Waiting for sveltejs/vite-plugin-svelte#202 before it's ready (EDIT: It's ready)

[bluwy]

Hmm, pnpm check is failing on Error: packages/kit check: ../../node_modules/.pnpm/vite@2.6.9/node_modules/vite/dist/node/index.d.ts(38,23): error TS7016: Could not find a declaration file for module 'ws'. '/home/runner/work/kit/kit/node_modules/.pnpm/ws@7.5.5/node_modules/ws/index.js' implicitly has an 'any' type. for both Vite 2.6.8 and 2.6.9. Note sure what happened there.

[bluwy]

Looks like vitejs/vite#5273 may have brought extra types that weren't properly generated

[bluwy]

I haven't had time to figure out a fix, but it seems to be an issue in Vite. I've reverted the commit for now.

[benmccann]

I filed an issue in Vite regarding the types bug: vitejs/vite#5338