WooCommerce Order Status Manager 1.15.4

* Fix - Ensure that the "pending" WooCommerce core order status cannot be set to other values than "needs payment" to avoid issues with some payment gateways

* Misc - Add compatibility for WooCommerce 4.7
* Misc - Require PHP 7.0 or newer
* Dev - Pass email object to hook that filters the order status email's body text

* Tweak - Improve the confirmation popup when the plugin is about to be deactivated with custom statuses in use