WooCommerce FedEx Shipping Method 3.9.6

* Fix - No shipping rates returned if the destination country don't require postcode.

* Fix - Improve Ground rate calculation when cart contain multiple different package types.
* Fix - FedEx International Ground rate calculation not always returned.
* Fix - FedEx International Ground rate returned under FedEx Ground name.
* Fix - REST API bearer token expiration time.
* Fix - FedEx Freight Class set on WC Shipping Class not being applied.

* Fix - Apply WordPress coding standard.

* Add - Phase out SOAP support.
* Fix - Woo Cart and Checkout Blocks compatibility when plain permalinks are set.

Add - Option to select package type.

* Fix - Package number in debug notification displaying PHP Warning.
* Fix - Invalidate stored Auth key in transient on credentials change.

Fix - Rates cache for SOAP and REST API.

* Fix - Freight shipment incompatibilities with Rate Service version 31.

* Fix - PHP8 Fatal Error on adding item to the cart when Parcel Packing Method is set to "Pack item individually".

* Update - FedEx Rate Service WSDL to version 31.