价格规则值-PriceRuleValue union
规则对价格产生影响的具体值。
可能的类型
[PriceRuleFixedAmountValue](https://shopify.dev/docs/admin-api/graphql/reference/discounts-and-marketing/pricerulefixedamountvalue)
[PriceRulePercentValue](https://shopify.dev/docs/admin-api/graphql/reference/discounts-and-marketing/pricerulepercentvalue)