z80pack Vulnerable to Exposure of the GITHUB_TOKEN in Workflow Run Artifact

z80pack is a mature emulator of multiple platforms with 8080 and Z80 CPU. In version 1.38 and prior, the `makefile-ubuntu.yml` workflow file uses `actions/upload-artifact@v4` to upload the `z80pack-ubuntu` artifact. This artifact is a zip of the current directory, which includes the automatically generated `.git/config` file containing the run's GITHUB_TOKEN. Seeing as the artifact can be downloaded prior to the end of the workflow, there is a few seconds where an attacker can extract the token from the artifact and use it with the Github API to push malicious code or rewrite release commits in your repository. This issue has been fixed in commit bd95916.