WooCommerce Square Payment Gateway 4.8.4

* Add - ESLint GitHub Action workflow to enforce ESLint rules on pull requests.
* Dev - Bump Square PHP SDK version from `29.0.0.20230720` to `35.1.0.20240320`.
* Dev - Improved codebase by addressing PHPCS errors.
* Dev - Improved codebase by resolving issues reported by ESLint.
* Dev - Address QIT PHPStan test errors.
* Dev - Address QIT Security test errors.
* Fix - A fatal error could occur when running incompatible versions of WooCommerce.
* Fix - Apple Pay button is now available on Cart and Checkout Block pages.
* Fix - Ensure that the 'Sync stock from Square' and 'Sync inventory' links work properly on the edit product screen.
* Fix - Prevent cancelled Digital Wallet payments from blocking the Checkout form.

* Dev - Bump WooCommerce "tested up to" version 8.9.
* Dev - Bump WooCommerce minimum supported version to 8.7.
* Fix - Update the Apple Pay domain verification file.

* Fix - Problem with connection to Square warning.
* Update - Refreshed plugin marketing copy in readme file.
* Update - Replace the middleware URL from `connect.woocommerce.com` to `api.woocommerce.com/integrations`.