Changes to Create subscription

the header request parameter idempotency-key became required

the request property card became required

the request property startDate became required

the response's body type changed from object to no type for status 201

removed the optional property code from the response with the 201 status

removed the optional property data from the response with the 201 status

removed the optional property message from the response with the 201 status

removed the optional property status from the response with the 201 status

the endpoint scheme security ApiKeyAuth was added to the API

the customer request property format was generalized from email to no format

added SuccessResponseDto subschema #2 to the response body allOf list for the response status 201

added the non-success response with the status 400

added the non-success response with the status 401

added the non-success response with the status 403

added the non-success response with the status 404

added the non-success response with the status 422

added the non-success response with the status 500