Pull Request: https://github.com/php/php-src/pull/22215
Author: XananasX7
This PR pins GitHub Actions from mutable version tags (e.g. @v4) to full commit SHAs,
preventing silent supply chain attacks from compromised action repositories.
Recommended by [GitHub's security hardening
guide](https://docs.github.com/en/actions/security-for-github-actions/security-guides/security-hardening-for-github-actions#using-third-party-actions)
and [OpenSSF Scorecard](https://securityscorecards.dev/).