Typed representation of a Coupon's applies_to restriction.
applies_to
When present, products lists the Product IDs this coupon is restricted to. When the parent Coupon's applies_to field is nil, the coupon has no product restrictions.
products
nil
@type t() :: %LatticeStripe.Coupon.AppliesTo{ extra: map(), products: [String.t()] | nil }
@spec from_map(map()) :: t()