Creates a usage plan key for adding an existing API key to a usage plan.
See https://www.paws-r-sdk.com/docs/apigateway_create_usage_plan_key/ for full documentation.
apigateway_create_usage_plan_key(usagePlanId, keyId, keyType)
[required] The Id of the UsagePlan resource representing the usage plan containing the to-be-created UsagePlanKey resource representing a plan customer.
[required] The identifier of a UsagePlanKey resource for a plan customer.
[required] The type of a UsagePlanKey resource for a plan customer.