Node compat

[Rich-Harris]

Following #10544 — we can do the same thing for Vercel and Netlify. Have just done Vercel so far

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🦋 Changeset detected

Latest commit: 81fd091

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

This PR includes changesets to release 2 packages

Name	Type
@sveltejs/adapter-vercel	Minor
@sveltejs/adapter-netlify	Minor

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[benmccann]

I'm not sure that adapter-vercel still needs the external option after this. Should we deprecate it and see if anyone's using it for something else? Or even drop it and make this a major release of the adapter?

[Conduitry]

@benmccann There was a brief conversation about that on Discord - https://discord.com/channels/457912077277855764/571775594002513921/1197729911771775057