Release 1.6.7

AKE2-9: Files are not available on the storefront
GRKAS1-29: Add configuration to customize ProductUnitPrecision
AKE2-10: Akeneo 4 support
GRKAS1-30: Given object is not an instance of the class this property was declared
KVSA1-35: Import performance when no changes where made on Akeneo side
KVSA1-36: Products unassigned from categories, while still assigned in Akeneo
KVSA1-40: Handle duplicate enum options
KVSA1-41: Product Connector (api step) performance issues
GRKAS1/KSVA1: Fix duplicate images