fix(vercel): add support for Node 22

[laymonage]

Changes

Add support for Node 22 on Vercel serverless. Fixes #446.

I'm not sure if this is the approach you'd like. If we have a default value for status, and Vercel uses the latest available version as the default, it seems we should've used whatever marked as default as the... default. Right now the code uses Node 18 instead, which is not what the SUPPORTED_NODE_VERSIONS constant suggests.

I considered making Node 22 the default, but I'm worried that it might be considered a breaking change.

Testing

I haven't tested it yet, don't have the time to do it right now but it seems like these changes should be enough to add the support?

Docs

The docs say

The @astrojs/vercel adapter supports specific Node.js versions for deploying your Astro project on Vercel. To view the supported Node.js versions on Vercel, click on the settings tab for a project and scroll down to “Node.js Version” section.
Check out the Vercel documentation to learn more.

Vercel already supports Node 22 now, so the docs are currently misleading, and adding the support will correct it.

[changeset-bot]

🦋 Changeset detected

Latest commit: 8a476e8

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

This PR includes changesets to release 22 packages

Name	Type
@astrojs/vercel	Minor
@test/astro-vercel-basic	Patch
@test/astro-vercel-function-per-route	Patch
@test/astro-vercel-image	Patch
@test/vercel-isr	Patch
@test/vercel-max-duration	Patch
@test/vercel-edge-middleware-with-edge-file	Patch
@test/vercel-edge-middleware-without-edge-file	Patch
@test/astro-vercel-no-output	Patch
@test/astro-vercel-prerendered-error-pages	Patch
@test/astro-vercel-redirects-serverless	Patch
@test/astro-vercel-redirects	Patch
@test/vercel-server-islands	Patch
@test/astro-vercel-serverless-prerender	Patch
@test/astro-vercel-serverless-with-dynamic-routes	Patch
@test/astro-vercel-static-assets	Patch
@test/astro-vercel-static	Patch
@test/vercel-streaming	Patch
@test/astro-vercel-with-speed-insights-enabled-output-as-server	Patch
@test/astro-vercel-with-speed-insights-enabled-output-as-static	Patch
@test/astro-vercel-with-web-analytics-enabled-output-as-static	Patch
vercel-hosted-astro-project	Patch

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[ematipico]

We can't make v22 the default because Astro itself doesn't officially support it.

[bluwy]

Doesn't out node version range allow node 22? https://github.com/withastro/astro/blob/cf0d8b08a0f16bba7310d1a92c82b5a276682e8c/packages/astro/package.json#L229 which technically means we support it. And it's also the active LTS now.

[ematipico]

Yeah, sorry, I misunderstood for Node.js v23 😓

[ematipico]

@bluwy should we point this PR against next? What do you think?

[bluwy]

I think it's fine in a minor, but our next major release is also not far away so that's fine by me too if you prefer to do so 👍