Change Rings\Classes\Data: should either be compatible with ArrayAccess

[GuglielmoPepe]

Deprecated: Return type of Rings\Classes\Data::offsetSet($offset, $value) should either be compatible with ArrayAccess::offsetSet(mixed $offset, mixed $value): void

[GuglielmoPepe]

These are the warnings raised with php 8.3:

1. Return type of \Rings\Classes\Data::offsetExists($offset) should either be compatible with ArrayAccess::offsetExists(mixed $offset): bool
2. Return type of \Rings\Classes\Data::offsetGet($offset) should either be compatible with ArrayAccess::offsetGet(mixed $offset): mixed
3. Return type of \Rings\Classes\Data::offsetSet($offset, $value) should either be compatible with ArrayAccess::offsetSet(mixed $offset, mixed $value): void
4. Return type of \Rings\Classes\Data::offsetUnset($offset) should either be compatible with ArrayAccess::offsetUnset(mixed $offset): void
5. Return type of \Rings\Classes\Data::count() should either be compatible with Countable::count(): int
6. Return type of \Rings\Classes\Data::getIterator() should either be compatible with IteratorAggregate::getIterator(): Traversable
7. Return type of \Rings\Classes\Data::jsonSerialize() should either be compatible with JsonSerializable::jsonSerialize(): mixed
8. Rings\Classes\Data implements the Serializable interface, which is deprecated. Implement __serialize() and __unserialize()