Add return types to normalizers

[ko4a]

Hi after upgrading symfony to 5.4 and php to 8.0 i got following deprecation notices:

Method "Symfony\Component\Serializer\Normalizer\DenormalizerInterface::denormalize()" might add "mixed" as a native return type declaration in the future. Do the same in implementation "Ekreative\UuidExtraBundle\Serializer\UuidNormalizer" now to avoid errors or add an explicit @return annotation to suppress this message.

Method "Symfony\Component\Serializer\Normalizer\DenormalizerInterface::supportsDenormalization()" might add "bool" as a native return type declaration in the future. Do the same in implementation "Ekreative\UuidExtraBundle\Serializer\UuidNormalizer" now to avoid errors or add an explicit @return annotation to suppress this message.

Method "Symfony\Component\Serializer\Normalizer\NormalizerInterface::normalize()" might add "array|string|int|float|bool|\ArrayObject|null" as a native return type declaration in the future. Do the same in implementation "Ekreative\UuidExtraBundle\Serializer\UuidNormalizer" now to avoid errors or add an explicit @return annotation to suppress this message.

Method "Symfony\Component\Serializer\Normalizer\NormalizerInterface::supportsNormalization()" might add "bool" as a native return type declaration in the future. Do the same in implementation "Ekreative\UuidExtraBundle\Serializer\UuidNormalizer" now to avoid errors or add an explicit @return annotation to suppress this message.

Could you please fix it? Or could i provide PR for fix it ?