Migrate to GitHub Actions and improve assertions

[peter279k]

Description

• Improve PHPunit assertions.
  • Using the assertCount to assert expected is same as result count.
  • Using the assertFalse to assert expected is false.
  • Using the assertNull to assert expected is null.
  • Using the assertTrue to assert expected is true.
• Migrating to the GitHub actions.
• Changing the PHPUnit version and PHP version semvers for supporting PHP-8.0 version test.