Deprecated function: Return type of Platformsh\Client\Model\ApiResourceBase::offsetExists($offset) should either be compatible with ArrayAccess::offsetExists(mixed $offset): bool

Hi, I encountered warnings when using this library with PHP 8.3.

We need to update the implementation of the ArrayAccess interface by adding parameter/return types to match the new method signature of this interface https://php.watch/versions/8.1/internal-method-return-types
