Force process exit to avoid cache hang

[frenchy64]

Related #108

See issue for context, seems related to this bug in Node 20. I ported the fix based on similar reports from other actions.

The implementation of actions/cache/save seems to do this too.

There's a related log that sometimes happens:

Failed to save: Unable to reserve cache with key setupclojure-linux-12-5-Babashka-1.12.194, another job may be creating this cache. More details: Cache already exists. Scope: refs/pull/1453/merge, Key: setupclojure-linux-12-5-Babashka-1.12.194, Version: 70a52b5fbf96614d479ae4de7af56ff6ff3227c9976f7b593da429d912efda06

I think the hang only happens if you dont see that log, which probably means a cache is being uploaded.

I created these conditions in this build and it finished in 2s.

Run DeLaGuardo/setup-clojure@2d31e3ee6005571f8b20ab9c0827f29238f58d88
/usr/bin/tar xz --warning=no-unknown-keyword --overwrite -C /home/runner/work/_temp/90c80a8b-bc29-4257-933f-17b5372d8e53 -f /home/runner/work/_temp/c8006cbd-ec86-47cc-ba08-f6283ea31b8f
/usr/bin/tar --posix -cf cache.tzst --exclude cache.tzst -P -C /home/runner/work/ctia/ctia --files-from manifest.txt --use-compress-program zstdmt
Cache Size: ~22 MB (23524[19](https://github.com/threatgrid/ctia/actions/runs/11638868025/job/32414265386#step:6:20)4 B)
Cache saved successfully