Add LLVM-Z80 - #277

Process completed with exit code 2.

Node.js 20 is deprecated. The following actions target Node.js 20 but are being forced to run on Node.js 24: actions/checkout@v4. For more information see: https://github.blog/changelog/2025-09-19-deprecation-of-node-20-on-github-actions-runners/

Summary report available at: https://github.com/gbdev/awesome-gbdev/actions/runs/38948540381#summary-117133754991