Fix multiple OpenAI-compatible function responses - #290

Node.js 20 is deprecated. The following actions target Node.js 20 but are being forced to run on Node.js 24: actions/cache@v4, shivammathur/setup-php@44454db4f0199b8b9685a5d763dc37cbf79108e1. For more information see: https://github.blog/changelog/2025-09-19-deprecation-of-node-20-on-github-actions-runners/