* Tweak - Remove legacy code. * Tweak - Introduced a more general REST endpoint (`shipment-trackings/providers`) for methods unrelated to specific order. * Tweak - UTF-8 support for custom providers.
* Tweak - WC 4.0 compatibility.
* Tweak - Move api to its own namespace at wc-shipment-tracking/v3/ old namespaces wc/v1 and wc/v2 are deprecated. * Tweak - WC 3.9 compatibility.
