Pin GitHub Actions to full-length commit SHAs - #83

Node.js 20 is deprecated. The following actions target Node.js 20 but are being forced to run on Node.js 24: actions/checkout@11d5960a326750d5838078e36cf38b85af677262, github/codeql-action/upload-sarif@42947a340483f03ba47bb1a039b2c519aab3df85. For more information see: https://github.blog/changelog/2025-09-19-deprecation-of-node-20-on-github-actions-runners/