Fix：3094 【商城小程序】多规格商品点击购物车图标并加购成功后，再次点击购物车图标打开规格选择页面，购买数量会保留上一次的值

mixins/goCartMixins.js

@@ -254,6 +254,8 @@ export default {
       postCartAdd(q).then(res => {
         this.isOpen = false
         this.attr.cartAttr = false
+        this.$set(this.attr.productSelect, 'cart_num', 1)
+        this.cart_num = 1
         uni.showToast({
           title: "添加购物车成功",
           icon: "none",
@@ -308,12 +310,15 @@ export default {
       // 修改了规格
       this.attr.cartAttr = msg
       this.$set(this.attr.productSelect, 'cart_num', 1)
+      this.$forceUpdate()
       this.isOpen = false
     },
     // 打开属性插件
     selecAttrTap() {
+      this.$set(this.attr.productSelect, 'cart_num', 1)
       this.attr.cartAttr = true
       this.isOpen = true
+      this.$forceUpdate()
     },
     ChangeAttr(res) {
       const { index, subIndex, value } = res