CI: Upgrade GitHub Actions to support Node.js 24 #2526

Per the official GitHub Changelog announcement, Node.js 20 has reached End-of-Life (EOL), and GitHub is actively phasing out support for it on Actions runners in favour of Node.js 24.

The enforcement schedule introduces key milestones that directly impact our workflows:

• June 2026: GitHub is switching the default runner execution behavior to Node.js 24. Actions explicitly targeting or running on Node.js 20 are actively triggering deprecation warning logs.
• Fall 2026: Node.js 20 will be fully removed from GitHub-hosted runners, which will cause any un-updated actions relying on it to fail.

To ensure our CI/CD pipelines remain stable, clear of warning noise, and future-proof, we need to audit and update the GitHub Actions versions used in .github/workflows/.

Proposed Changes

1. Audit Workflow Files: Check all YAML files in .github/workflows/ for third-party or official GitHub actions targeting Node.js 20.
2. Upgrade Action Versions: Bump outdated GitHub Actions to versions that natively target the node24 runtime. Major dependencies to look for typically include:

• actions/checkout (Ensure it is at least v4/v5+)
• actions/setup-node
• actions/cache
• actions/upload-artifact / actions/download-artifact
• WordPress-specific custom actions or third-party community actions.