Upgrade minimal supported version of Node.js to 20

[bliuchak]

Currently project works under Node 18 which reached its EOL on April 30, 2025. It will no longer receive security updates or maintenance releases.

Plan it to upgrade to version 22 or 24 (current LTS). New plan is to support last 3 LTS versions of Node.js. As of today they are: 24, 22 and 20.

Note: this won't be an easy task since there are breakable changes.

Refs: https://nodejs.org/en/blog/announcements/node-18-eol-support

[jirimoravcik]

We need to maintain backwards compatibility with older versions of Node.js

[raethlo]

Move to pre-backlog (zenhub down atm)

Note from grooming: this sounds like a lot of work, @bliuchak & @lewis-wow will talk to @fnesveda and assess how to safely migrate (do we need to support both 18 and next LTS) and what the prio is compared to other things.