WooCommerce Xero 1.9.0

* Fix - Use a separate country list for the report tax type when creating a tax rate in Xero.
* Dev - Update secret key encryption to use the Sodium library for token encryption.
* Dev - Upgrade the `xeroapi/xero-php-oauth2` SDK from version 2.20.0 to version 7.2.0.
* Dev - Bump WooCommerce "tested up to" version 9.4.
* Dev - Bump WooCommerce minimum supported version to 9.2.
* Dev - Bump WordPress minimum supported version to 6.5.
* Dev - Remove Xero OAuth 1.0 Authentication as it is fully deprecated.

* Fix - PHPCompatibility errors reported by the QIT test.
* Dev - Bump WooCommerce "tested up to" version 9.2.
* Dev - Bump WooCommerce minimum supported version to 9.0.
* Dev - Fix QIT E2E tests and add support for a few new test types.

* Dev - Bump WooCommerce "tested up to" version 9.1.
* Dev - Bump WooCommerce minimum supported version to 8.9.
* Dev - Bump WordPress "tested up to" version 6.6.
* Dev - Exclude the Woo Comment Hook `@since` sniff.

* Dev - Bump WooCommerce "tested up to" version 9.0.
* Dev - Bump WooCommerce minimum supported version to 8.8.
* Dev - Bump WordPress minimum supported version to 6.4.
* Dev - Update NPM packages and node version to v20 to modernize developer experience.

* Add - Masked the client ID and client secret fields to add an extra layer of confidentiality and protection.
* Dev - Bump WooCommerce "tested up to" version 8.5.
* Dev - Bump WooCommerce minimum supported version to 8.3.
* Dev - Bump WordPress minimum supported version to 6.3.

* Add - Indicate compatibility with WooPayments extension.
* Add - Indicate compatibility with WooCommerce Blocks.
* Dev - Update PHPCS and PHPCompatibility GitHub Actions.
* Dev - Bump WooCommerce "tested up to" version 8.4.
* Dev - Bump WooCommerce minimum supported version to 8.2.
* Dev - Bump PHP minimum supported version to 7.4.
* Fix - Resolved PHP deprecation warnings on `strpos` and `preg_replace`.
* Tweak - Bump PHP "tested up to" version 8.3.

* Dev - Added critical flows end-to-end tests.
* Dev - Bump Woocommerce Requires at least 8.1.
* Dev - Bump Woocommerce Tested up to version 8.3.
* Dev - Bump WordPress "tested up to" version 6.4.
* Dev - Bump WordPress minimum supported version to 6.2.
* Fix - Ensure that the invoice is sent to Xero "on order creation" when an order is placed through the block-based checkout.
* Fix - Salt rotation issue affecting encrypted keys.

* Dev - Bump `clean-css-cli` from 5.6.1 to 5.6.2.
* Tweak - Bump WooCommerce tested up to 7.3.
* Tweak - Bump tested up to WordPress version 6.1.
* Tweak - Improve SSL certificate verification.

* Bump tj-actions/changed-files from 34 to 35.
* Dev - Bump `codedungeon/phpunit-result-printer` from 0.5.0 to 0.9.3.
* Dev - Bump `node-sass` from 7.0.3 to 8.0.0.
* Dev - Bump `node-wp-i18n` from 1.2.6 to 1.2.7.
* Dev - Bump `phpunit/phpunit` from 6.5.9 to 6.5.14.
* Tweak - Add links to extension requirements on the settings page.

* Add - Declare compatibility for High-performance Order Systems ("HPOS").
* Add - Option to enable/disable use of customer email in the contact name.
* Change - Ensure tokens are encrypted before we store them.