Fix CVE-2025-6965 + .NET 10 - #74

Node.js 20 is deprecated. The following actions target Node.js 20 but are being forced to run on Node.js 24: 5monkeys/cobertura-action@v13, actions/checkout@v3, actions/setup-dotnet@v3, actions/setup-java@v4.0.0. For more information see: https://github.blog/changelog/2025-09-19-deprecation-of-node-20-on-github-actions-runners/