chore(deps): bump actions/setup-java from 4.9.1 to 6.0.0 - #709

Node.js 20 is deprecated. The following actions target Node.js 20 but are being forced to run on Node.js 24: actions/dependency-review-action@3b139cfc5fae8b618d3eae3675e383bb1769c019. For more information see: https://github.blog/changelog/2025-09-19-deprecation-of-node-20-on-github-actions-runners/