Teams for Woocommerce Memberships 1.7.5

* Fix - Prevent fatal error triggered while processing a subscription renewal from the admin dashboard
* Fix - Prevent number of seats to increase on teams with per-team pricing when a subscription renewal is processed
* Fix - Fix a logic error that could cause renewal links for team memberships not to work

* Misc - Add support for WooCommerce 4.0

* Misc - Add a documentation resource for teams with unlimited seats affected by the bug fixed in v1.2.1