feat: Drop Node.js v20

[nschonni]

Description

Drop v20 images, and remove the ppc64le from the architectures. Not sure if that should also be cleaned out of the template now too.

Motivation and Context

Node.js 20 hits EOL on April 30th. Opening as a draft, as I'm not sure if there will be a final release.

Testing Details

Example Output(if appropriate)

Types of changes

• Documentation
• Version change (Update, remove or add more Node.js versions)
• Variant change (Update, remove or add more variants, or versions of variants)
• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)
• Other (none of the above)

Checklist

• My code follows the code style of this project.
• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• I have read the CONTRIBUTING.md document.
• All new and existing tests passed.

[MikeMcC399]

https://hackmd.io/@openjs-nodejs/By6_V87jWx shows

Release plan - v20.x Maintenance LTS #855
No more planned releases.

https://github.com/nodejs/node/blob/main/doc/changelogs/CHANGELOG_V20.md shows the last one was

https://github.com/nodejs/node/blob/main/doc/changelogs/CHANGELOG_V20.md#20.20.2 security release
2026-03-24, Version 20.20.2 'Iron' (LTS), @marco-ippolito

[nschonni]

Thanks for confirming! Still makes sense to hold off landing this, as it will stop any rebuilds for the base images

[sxa]

Approving but +1 one holding off until the date has passed. You worried me a bit with "Remove the ppc64le from the architectures" in the description as it wasn't clear that it was specific to Alpine and wasn't removing the Debian images ;-)