Add ability to check for multiple extends

[kapersoft]

This PR adds the ability to add multiple parameters in the Extends constructor. The violation will happen when none of the given strings will match the extend.

In my project I want to check if unit tests extends PHPUnit's TestCase or Mockery's TestCase:

return static function (Config $config): void {
    $testClassSet = ClassSet::fromDir(__DIR__ . '/Tests');

    $rule = Rule::allClasses()
        ->that(new ResideInOneOfTheseNamespaces('Tests\Unit'))
        ->andThat(new HaveNameMatching('*Test'))
        ->should(new Extend(\PHPUnit\Framework\TestCase::class, \Mockery\Adapter\Phpunit\MockeryTestCase::class))
        ->because('unit tests must extend the PHPUnit TestCase or Mockery TestCase');

    $config->add($testClassSet, $rule);
};

When one parameter is used in the Extend constructor, it works the same as before.

[AlessandroMinoccheri]

Hi @kapersoft thanks for this PR, can you please also update the README file with this new behavior?

[kapersoft]

@AlessandroMinoccheri I have applied the same changes to the NotExtend-class and updated the readme.md

[AlessandroMinoccheri]

Little fix to do @kapersoft for coding standards, then it can be merged.

[kapersoft]

@AlessandroMinoccheri ✅ Done.

[AlessandroMinoccheri]

LGTM 👍

[kapersoft]

Thanks! 👍