Update to support exiring access tokens?

[tomatic]

Shopify introduced expiring access tokens in Dezember 2025. Right now you have to explicitly request them by using expiring=1 in the request. But I would expect them to become mandatory at some point.

Can we expect php-shopify to add support for these?

[tareqtms]

@tomatic
It would be good if you could create a PR. Thanks.
(Otherwise, I will check later)