Reusable remark workflow: bump Node from 20 to 24

[rodrigoprimo]

Description

The QA Markdown job has been failing across the org with the following error:

TypeError: webidl.util.markAsUncloneable is not a function

dead-or-alive@1.0.5, pulled in transitively via remark-lint-no-dead-urls, bumped undici to ^8. undici@8 calls markAsUncloneable, a Node API only available from Node 22.10.0, while the workflow uses Node 20.

This PR bumps node-version to "24", which fixes the failure and also moves CI off Node 20 (end of life).

Fixes the failing QA Markdown check on open PRs across the org. Examples: PHPCSStandards/PHPCSExtra#439 and PHPCSStandards/PHP_CodeSniffer#1438.

How this was tested

I tested this change using act on my machine with the following temporary workflow file:

name: Node version test
on: [workflow_dispatch]
jobs:
  call:
    uses: ./.github/workflows/reusable-remark.yml

gh act workflow_dispatch -W .github/workflows/node_version_test.yml

On main the job crashes with the markAsUncloneable error. On this branch it loads .remarkrc and lints successfully.

[jrfnl]

Thanks @rodrigoprimo ! One question: why Node 22 ? What I mean by that is: why not bump to Node 24 while we're at it ? Is there anything which would currently block that ?

[rodrigoprimo]

Good question! I think what happened is that I saw [markAsUnclonable](https://nodejs.org/api/worker_threads.html#worker_threadsmarkasuncloneableobject) was added in Node 22 and bumped to this version without considering newer versions.

I can confirm that everything works with Node 24. I force pushed the original commit and updated the description and title. This PR now suggests updating to Node 24.

[jrfnl]

Thanks for the update @rodrigoprimo ! All good from me.