#47 updated the adapter to target Node 16 instead of 12. This is good, but it would be better if we could allow the user to specify which node version to use. Otherwise, they'll be tied to the adapter Node version.
Here's how adapter-vercel does it:
https://github.com/sveltejs/kit/blob/3dae8e702641b5ee762b1892b7b7aa90e1c19a7c/packages/adapter-vercel/index.js#L388-L399