Update art4/json-api-client

[Art4]

Full discloser: I'm the author of the library art4/json-api-client that you are using in this project.

Hi :wave:

I've recently release JsonApiClient v0.10 that introduces some changes and deprecates many classes.

This PR uses the latest changes to avoid the deprecated classes. Also this changes will allow you to switch to v1.0 as soon as it is released.

This PR is untested, because there are no tests and I havn't read yet how to use the Patreon API. So please review and test this PR before merging.

Also I'm ready to help if there are questions or the need of features in JsonApiClient.

I'm glad if I could help you.

[nperickson]

Hey @Art4! Thank you so much for doing this for us. It may be a bit before we merge this as it's pretty low priority right now, but our team is very thankful none the less!

[jakubboucek]

Thit PR is no more relevant because package art4/json-api-client removed at #58.