WooCommerce Square Payment Gateway 4.8.4

* New - Make the "Update existing products" part of the new import process optional by adding a new checkbox on Import Products modal. PR#508
* Fix - Stop the import process from getting stuck in a loop when reaching the time limit. PR#511
* Fix - Don't import/update categories from Square that are attached to products that cannot be found in WooCommerce. PR#511
* Fix - "idempotency_key must not be greater than 45 length" errors returned by some payment requests on stores using custom order number plugins. PR#507

Fix – Fatal errors caused by incorrectly fetching locations before plugin init.
Fix – WordPress database error when creating the Square Customers table on servers using utf8mb4.

* Fix - Make sure that Square credit card fields are editable after checkout form refresh.