WooCommerce USPS Schriffmethode 5.5.6

* Update QIT Tests Job Based on WC Team Recommendation.
* WOOUSPS-14 - WooCommerce 10.0 Compatibility.

* Tweak - WooCommerce 9.9 compatibility.

* Replace ubuntu-20.04 with ubuntu-latest in GitHub Actions.
* Update Requires headers for WooCommerce compatibility.

* Tweak - WooCommerce 9.7 Compatibility.

* Tweak - PHP 8.4 Compatibility.

* Tweak - WordPress 6.7 and WooCommerce 9.3 compatibility.

* Tweak - WordPress 6.6 and WooCommerce 9.0 Compatibility.

* Fix - Corrected deprecated null parameter to comply with updated PHP standards.

Fix - Removed WC_Boxpack class_exists check as it is no longer needed.

Fix - Apply WordPress coding standards.