ci(node.js): build and test with even versions of Node.js

[bytrangle]

Summary

I've noticed that even PRs that just involve documentation changes have failed recently due to new Node.js version.

I'm changing the Node.js workflow to only build and test on even versions, which enjoy LTS.

Some modules require Node.js no older than certain number. Please tell me if there's a more robust way to declare Node.js versions.

Test plan

I'm not really sure how to test it on my part. Appreciate any pointer.

Checklist

Please add a x inside each checkbox:

• [x] I have read the contribution guidelines.
• [x] Code is formatted via running yarn format.
• [x] Tests are passing via running yarn test.
• [x] The status checks are successful (continuous integration). Those can be seen below.