Changes to Create a gift card

added the new required request property data/relationships/gift_card_recipient/data

added the new required request property data/relationships/market/data

request property data/type was restricted to a list of enum values

the data/attributes/balance_max_cents request property type changed from string to integer

removed the request property data/relationships/gift_card_recipient/id

removed the request property data/relationships/gift_card_recipient/type

removed the request property data/relationships/market/id

removed the request property data/relationships/market/type

added the new optional request property data/attributes/distribute_discount

added the new optional request property data/relationships/tags

the type request property default value gift_cards was removed

added the new gift_cards enum value to the request property data/type

added the media type application/vnd.api+json for the response with the status 201