WooCommerce Google Analytics Pro 2.2.0

* Fix - Make sure Subscriptions event names settings are displayed in the Google Analytics Pro admin settings page
* Fix - Ensure the "completed purchase" event is tracked when payment is recorded
* Dev - Pass a product argument in `wc_google_analytics_pro_product_details_data` and `wc_google_analytics_pro_product_impression_data` filters

*Misc - Drop support for PHP 5.2: PHP 5.4 is now the minimum required version
* Misc - Update Google API client library to v2.2.2
* Misc - Update the SkyVerge Plugin Framework to v5.2.0

* Tweak - Subscription renewals will now send their event value in cents by default
* Fix - Set a client identity on Subscriptions created before Google Analytics Pro was activated so they can be correctly tracked when renewed
* Fix - Ensure Subscriptions events exist in settings before attempting to track them to avoid PHP errors
* Fix - Ensure orders processed with the Cash on Delivery gateway are fully tracked
* Dev - Add a filter to toggle whether to use cents or dollars in completed purchase, refunds or renewed subscriptions events value