Fix TypeScript-only syntax in docs snippets embedded as JavaScript - #519

Node.js 20 is deprecated. The following actions target Node.js 20 but are being forced to run on Node.js 24: ./.github/.release/actions/actions/validators/pubnub-yml, actions/checkout@v4. For more information see: https://github.blog/changelog/2025-09-19-deprecation-of-node-20-on-github-actions-runners/