[Proposal] Upgrade to Node.js from 14 to 18

[seanneumann]

Is your feature request related to a problem? Please describe.

Today, OpenSearch Dashboards runs on Node 14, which has longterm support (LTS) until April of 2023 (https://github.com/nodejs/release#release-schedule).

Describe the solution you'd like

I'd like to consider upgrading to Node 18 which has active support through 2025.

Describe alternatives you've considered

We can consider Node 16, but it ends support in September of 2023. It doesn't make sense to me to upgrade to a version as it ends support.

Note, previous effort: #406

[tmarkley]

Definitely agree that v18 is the right path. I'm assuming this should be targeted for v3.0? If so, who's overseeing the project to ensure that the details are hashed out in time? I think we learned a lot from the previous Node.js upgrade and we should expect there to be a lot of unknowns along the way. I expect many prerequisite changes before this gets across the finish line. Bishoy already documented the hurdles that prevented us from upgrading to v16: #406 (comment)

[hashworks]

Some time has passed, and I don't think 18 would make sense - its maintenance support ends 2025-04. 20 would be a better fit.