CI unit tests failure

Describe the bug

events.js:292
      throw er; // Unhandled 'error' event
      ^

Error [ERR_IPC_CHANNEL_CLOSED]: Channel closed
    at process.target.send (internal/child_process.js:705:16)
    at Worker.send (internal/cluster/worker.js:46:10)
    at ClusterWorker.sendToMainWorker (/home/runner/work/poolifier/poolifier/lib/worker/cluster-worker.js:21:282)
    at ClusterWorker.checkAlive (/home/runner/work/poolifier/poolifier/lib/worker/abstract-worker.js:27:178)
    at listOnTimeout (internal/timers.js:554:17)
    at processTimers (internal/timers.js:497:7)
Emitted 'error' event on Worker instance at:
    at process.<anonymous> (internal/cluster/worker.js:30:12)
    at process.emit (events.js:315:20)
    at processEmit [as emit] (/home/runner/work/poolifier/poolifier/node_modules/signal-exit/index.js:161:32)
    at internal/child_process.js:709:35
    at processTicksAndRejections (internal/process/task_queues.js:75:11) {
  code: 'ERR_IPC_CHANNEL_CLOSED'
}

Steps to reproduce the behavior

Do a test PR on the repository

Expected behavior

Unit tests should work on GitHub CI GitHub shall not mark the unit tests run as successful

Info

Tool	Version
Poolifier	v2.x.x
Node	v1x.x.x
OS	linux

[pioardi]

The issue were present on our unit tests, we were not using our pool methods to clean up the child processes, so when mocha terminated the tests the shutdown was not graceful. What we did is shutdown the cluster pools gracefully before to finish our test cases.

Issue should be now totally fixed, in future we should always destroy our pools after the tests to avoid similar issues.

[pioardi]

I think that this is because we execute worker.kill() but we should first clear the interval.