How far should we update Node version?

[harsh183]

Now that we have node version upgrades unlocked, we need to decide how far to upgrade. The major choices at the moment are: 18, 20 (LTS and official default on the site) and 22 (latest stable).

Looking at support https://nodejs.org/en/about/previous-releases, 16 (CT currently) is past maintenance, 18 will be maintained till 2025 and 20 will be maintained till 2026. Node v22 is currently marked as active.

Looking at https://node.green/ - Node 18 covers basically all the major features upto ECMA Script 2023, so we won't miss any major JS features, it'll come down to what our package upgrades support basically.

[harsh183]

With #789 merged, we're now on 18, we should be fine for now but we can reopen this if anyone has a good reason to also move onto later versions.