Support node 20 (or anything > 18.17.1)

Please add support for node 20, to keep up with Oryx and the world.

The current version of NextJs is 14, but it is barely possible to deploy:
NextJs 14 requires node: '>=18.17.0', but if I specify that in my 'engines' section, Oryx selects 20.0.9, and static-web-apps fails with "Node version 20.9.0 is not supported. Please use one of the following versions 12, 14, 16, 18."

The **single** node version currently supported by both nextjs 14 _and_ the platform is 18.17.1, and it has to be hard coded all the way
But even that tiny window is closing:

Node 18 is entering maintenance mode as we speak (december 2023), and end-of-life in just 5 months.
Nextjs release major versions every year, bumping the node requirement past any dead versions.

So this is a ticking bomb for anyone wanting to use new features of fixes in nextjs.