chore: update Node.js version to 20.x

[matifali]

This builds fine except for a few tests. I would appreciate it if someone from @coder/eng could take this from here.

I considered this update to see dependabot failing to update as GitHub now uses Node 20.

To resolve that, why not bump to Node20, given it's the current LTS release?

Also closes #12954

[matifali]

THIS IS NOT URGENT AND SHOULD NOT DISTURB YOUR EXISTING INVOLVEMENTS.

@BrunoQuaresma, when you have time, would you take this over to completion and also check #12954? Thank you :)

[aslilac]

looks like 22 just released. might be worth shooting straight for that if we can.

[matifali]

Node 22 will be promoted to LTS in October and then I guess packages will take at least another few months to a year to catch up to 22.
So we have to wait at least a year.

This migration to node 20 is almost complete except 4 or 5 tests failing that I couldn't figure out.

So feel free to take it over if you want.

@aslilac