vant-stepper 添加了一个用于控制 change 触发时机的属性

What problem does this feature solve? The triggering time of the change event in the current vant-stepper component feels incorrect. The change event of vant-stepper should indicate the change triggered by the component. However, if we modify the content by controlling the value bound to the v-model, the change event will also be triggered, resulting in some business scenarios that cannot be met. For example: There are three input scenarios for three stepper components: quantity, unit price, and total price. These three prices should be kept in sync. That is, when the unit price changes, the total price should be modified by JavaScript code, but after the total price is modified, the change event for the total price will be triggered (it is not desirable to trigger the change event for the total price in business).