Remove unnecessary include for variant in inventory_units for Shipment#to_package
Add missing backtick for Core's changelog
set default for api config require_authentication back to true.

skip filters on frontend for coupon_code bypass the require_authentication setting on backend specs.

Signed-off-by: Peter Berkenbosch <peter@pero-ict.nl>

Fixes #4165
typo on spec_helper template for extensions

Fixes #4247