Add note that 'No shipping methods placeholder when they are all disabled' requires WC 4.3

Author: Aljullu

docs/testing/releases/270.md

@@ -74,6 +74,7 @@ You'll need to be logged in with a user that has saved payment methods.
 4. Submit the checkout and this should result in the purchase completing successfully for the cheque payment method.
 
 ### No shipping methods placeholder when they are all disabled (#2543)
+_(Requires at least WooCommerce 4.3)_
 1. Disable all shipping methods from your store.
 2. Edit a page with the _Checkout_ block and verify the 'no shipping methods' placeholder appears.