[release/v7.6.7] Bump actions/setup-dotnet from 5.3.0 to 6.0.0 - #28161

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@2031cfc080254a8a887f58cffee85186f0e49e48. For more information see: https://github.blog/changelog/2025-09-19-deprecation-of-node-20-on-github-actions-runners/