chore: upgrade GitHub Actions from Node.js 20 to Node.js 24

[superdav42]

Problem

GitHub Actions is deprecating Node.js 20. Actions running on Node.js 20 will be forced to Node.js 24 starting June 2, 2026, and Node.js 20 will be removed from runners on September 16, 2026.

This repo's workflows use actions that still run on Node.js 20, producing deprecation warnings on every run.

Required upgrades

Current	Upgrade to
actions/checkout@v4	actions/checkout@v6
actions/setup-node@v4	actions/setup-node@v6

shivammathur/setup-php@v2 is already on Node 24 (v2.37.0) -- no change needed.

How

EDIT: .github/workflows/*.yml -- find-and-replace the action version tags per the table above.

For softprops/action-gh-release, add this env var to the workflow or job level until upstream releases a Node 24 version:

env:
  FORCE_JAVASCRIPT_ACTIONS_TO_NODE24: true

Verification

After merging, trigger a workflow run and confirm no Node.js 20 deprecation warnings appear in the annotations.

References

• GitHub blog: Deprecation of Node 20 on GitHub Actions runners