enhance the serializer tests

[binaryk]

Fixed

• enhance the serializer tests

[what-the-diff[bot]]

PR Summary

• A new configuration file (pint.json) was added, which sets some rules for the project. This provides better control over the project settings.
• The RoutesDefinition.php, PublishAuthCommand.php, and several other files had some of their function parameters modified to accept not only specific types like string, array or int but also null values. This increases the flexibility of these functions as they can now handle more diverse inputs.
• The MailTracking.php, PostsShowGetter.php, PostPolicy.php, IntegrationTestCase.php, and Prototypeable.php files underwent similar changes for the same reason: to expand their versatility when handling null values.
• A test was changed in RepositorySerializerTest.php to check for the existence of data.0.relationships.user and to confirm that the data.0.type value is 'posts'. This change helps to ensure the integrity and correctness of the data structure in our application.