* Feature - Added setting for defining the rates refreshing period.
* Tweak - Validate the App ID on settings save.
* Tweak - Tested compatibility up to WC 7.5.
* Tweak - Tested compatibility with WP 6.2.
* Dev - Log errors from the Open Exchange Rates API requests.
* Dev - Initialize the plugin when the main file is loaded.
* Dev - Removed trailing underscore from the filter hook `wc_currency_converter_settings_api_form_fields`.
* Dev - Dropped deprecated code from versions 1.x.
* Dev - Updated the minimum requirements to WC 3.7, WP 4.9, and PHP 5.6.
* Tweak - WP tested up to 6.0.
* Tweak - WC tested up to 6.5.
* Tweak - WC tested up to 6.1.
* Tweak - WP tested up to 5.9.
* Fix - Sanitize currency codes before including in JS on the frontend.
* Fix - Fix issues with conversion functionality in shortcodes.
* Tweak - Reduce the size of wc_currency_converter_params.
* Tweak - WC tested up to 6.0.
* Tweak - WP tested up to 5.8.