ci: make unit tests run in parallel

[PouriaAmini]

Summary

This PR adds support for running unit tests in parallel for all Apple platforms.

Checklist

• [x] Does your PR title have the correct title format?
• Does your PR have a breaking change?: no

[github-actions[bot]]

:tada: This PR is included in version 1.8.1 :tada:

The release is available on:

• GitHub release
• v1.8.1

Your semantic-release bot :package::rocket: