* Feature - Added setting for changing the location of the subscription field in the checkout form.
* Tweak - Reorganized the subscription settings fields.
* Tweak - Tested compatibility with WC 5.5.
* Tweak - Tested compatibility with WP 5.8.
* Dev - Deprecated the `wc_newsletter_subscription_checkout_content_location` filter in favor of `wc_newsletter_subscription_checkout_locations`.