add note about setting node version (#5068)

* add note about setting node version

* update screenshot

* compact image

* Update packages/adapter-vercel/README.md

Co-authored-by: Ben McCann <322311+benmccann@users.noreply.github.com>

Co-authored-by: Conduitry <git@chor.date>
Co-authored-by: Ben McCann <322311+benmccann@users.noreply.github.com>

Author: 3 people

packages/adapter-vercel/README.md

@@ -38,8 +38,16 @@ export default {
 
 ## Notes
 
+### Vercel functions
+
 Vercel functions contained in the `/api` directory at the project's root will _not_ be included in the deployment — these should be implemented as [endpoints](https://kit.svelte.dev/docs/routing#endpoints) in your SvelteKit app.
 
+### Node version
+
+Projects created before a certain date will default to using Node 14, while SvelteKit requires Node 16 or later. You can change that in your project settings:
+
+![Vercel project settings](settings.png)
+
 ## Changelog
 
 [The Changelog for this package is available on GitHub](https://github.com/sveltejs/kit/blob/master/packages/adapter-vercel/CHANGELOG.md).