Publish Warning: "Cache save failed."

[david-allison]

https://github.com/ankidroid/Anki-Android-Backend/actions/runs/8516371828/job/23325301459#step:16:25

/opt/homebrew/bin/gtar --posix -cf cache.tzst --exclude cache.tzst -P -C /Users/runner/work/Anki-Android-Backend/Anki-Android-Backend --files-from manifest.txt --delay-directory-restore --use-compress-program zstdmt
Failed to save: Unable to reserve cache with key macOS-rust-release-v6-41bba980dae4fee99e1deaaa8d55d24c72e5f2497c4fc262204a747ff667876d-[23](https://github.com/ankidroid/Anki-Android-Backend/actions/runs/8516371828/job/23325301459#step:16:24)b68d010ec8a0236c8f08d540479c6d59a85170c60478b901bffbb384b959b9, another job may be creating this cache. More details: Cache already exists. Scope: refs/heads/main, Key: macOS-rust-release-v6-41bba980dae4fee99e1deaaa8d55d24c72e5f2497c4fc262204a747ff667876d-23b68d010ec8a0236c8f08d540479c6d59a85170c60478b901bffbb384b959b9, Version: b2972dbfc77cf5f32f328d39739862509aa79c09d44c3e5ae42dd89509b69af3