Fix vuln-triage-reporter YAML frontmatter - #471

Node.js 20 is deprecated. The following actions target Node.js 20 but are being forced to run on Node.js 24: danhellem/github-actions-pr-is-linked-to-work-item@main. For more information see: https://github.blog/changelog/2025-09-19-deprecation-of-node-20-on-github-actions-runners/