Update AmmoThing.cs - #4699

Node.js 20 is deprecated. The following actions target Node.js 20 but are being forced to run on Node.js 24: actions-ecosystem/action-add-labels@v1, actions/checkout@v3, peter-evans/create-or-update-comment@v2. For more information see: https://github.blog/changelog/2025-09-19-deprecation-of-node-20-on-github-actions-runners/