Update supported Node.js and NPM versions

[alanorth]

Description

Update supported Node.js and NPM versions. As of this writing, the status of Node.js versions is currently:

• v18 — end of life since 2025-04-30 ⚠️
• v20 — maintenance LTS until 2026-04-30
• v22 — maintenance LTS until 2027-04-30
• v24 — active LTS, supported until 2028-04-30

We should officially only be supporting currently supported Node.js releases that are under maintenance by upstream. The project may or may not build/run with other versions.

Instructions for Reviewers

Please add a more detailed description of the changes made by your PR. At a minimum, providing a bulleted list of changes in your PR is helpful to reviewers.

List of changes in this PR:

• Update package.json to declare supported Node.js and NPM engine versions
• Update README.md to declare supported Node.js and NPM versions
• Update GitHub actions to use a matrix of Node.js versions: v20, v22, and v24
• Update Dockerfiles to use minimum supported Node.js (v20)

Include guidance for how to test or review your PR. This may include: steps to reproduce a bug, screenshots or description of a new feature, or reasons behind specific changes.

Checklist

This checklist provides a reminder of what we are going to look for when reviewing your PR. You do not need to complete this checklist prior creating your PR (draft PRs are always welcome).
However, reviewers may request that you complete any actions in this list if you have not done so. If you are unsure about an item in the checklist, don't hesitate to ask. We're here to help!

• My PR is created against the main branch of code (unless it is a backport or is fixing an issue specific to an older branch).
• My PR is small in size (e.g. less than 1,000 lines of code, not including comments & specs/tests), or I have provided reasons as to why that's not possible.
• My PR passes ESLint validation using npm run lint
• My PR doesn't introduce circular dependencies (verified via npm run check-circ-deps)
• My PR includes TypeDoc comments for all new (or modified) public methods and classes. It also includes TypeDoc for large or complex private methods.
• My PR passes all specs/tests and includes new/updated specs or tests based on the Code Testing Guide.
• My PR aligns with Accessibility guidelines if it makes changes to the user interface.
• My PR uses i18n (internationalization) keys instead of hardcoded English text, to allow for translations.
• My PR includes details on how to test it. I've provided clear instructions to reviewers on how to successfully test this fix or feature.
• If my PR includes new libraries/dependencies (in package.json), I've made sure their licenses align with the DSpace BSD License based on the Licensing of Contributions documentation.
• If my PR includes new features or configurations, I've provided basic technical documentation in the PR itself.
• If my PR fixes an issue ticket, I've linked them together.

[tdonohue]

@alanorth : Note this PR overlaps a bit with the new Angular 20 upgrade, which also updates us to Node.js v20 and v22. See #4804

[alanorth]

@tdonohue Ah OK great. I can wait until that is merged and then update depending on what needs to be adjusted. We should be targeting v20, v22, and v24 since those are all currently supported LTS releases.

[tdonohue]

@alanorth : While I understand the desire to target all three Node.js supported versions, we do have to keep in mind that we have a limited number of "free" build hours available in GitHub. So, doing 3 builds per dspace-angular PR might risk us going over that limit.

That's why we've tended to choose two Node.js versions to run the build on.... I'd love to do three, but I'm not sure it's possible unless we start paying for GitHub builds.

[alanorth]

So, doing 3 builds per dspace-angular PR might risk us going over that limit.

Sure, got it. Then we should target v22 and v24. :)

[mwoodiupui]

v20 will be EOL in only about six months so it isn't much of a loss.

[github-actions]

Hi @alanorth,
Conflicts have been detected against the base branch.
Please resolve these conflicts as soon as you can. Thanks!