Replace the retired gpt-3.5-turbo default for openai.com - #342

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, azure/CLI@9f7ce6f37c31b777ec6c6b6d1dfe7db79f497956, microsoft/security-devops-action@08976cb623803b1b36d7112d4ff9f59eae704de0. For more information see: https://github.blog/changelog/2025-09-19-deprecation-of-node-20-on-github-actions-runners/