Merge pull request #805 from quazardous/v5.0-compat

[v5] Fix enum constants

Merge pull request #806 from iajrz/fixes-796

Fixes 796

Fix Singapore seller central URL

Fix OAuth token endpoint

Add App Integrations API

Correctly generate complex array response types

Merge pull request #753 from simonsolutions/patch-4

Update ShippingService.php

Expand timezone deserialization tests

Update cache parameter documentation

Update package version to 7.0.2