WooCommerce Royal Mail / Royal Mail Shipping Method for WooCommerce 3.5.6

* Tweak - WooCommerce 10.0 Compatibility.

Tweak - WooCommerce 9.9 Compatibility.

* Update Requires headers for WooCommerce compatibility.
* Update to ubuntu-latest to fix QIT tests.

* Fix - Parcelforce Global Express EU rates.

* Update - Update Parcelforce international pricing.
* Tweak - PHP 8.4 Compatibility.

* Tweak - WordPress 6.7 compatibility.

* Update - Update pricing based on October 2024 rates.

* Add - "Available on" display to indicate the rates availability.
* Update - Update online rate pricing based on July 2024 rates.
* Tweak - WordPress 6.6 Compatibility.

* Update - Update pricing based on April 2024 rates.

* Fix - WordPress Coding Standards.