Fix(商品)：多规格商品在选购时，选择第一个规格增加数量，再改选第二个规格，数量不会刷新，但立即购买，订单页面数量显示为“1”

pages/shop/GoodsCon/index.vue

@@ -376,6 +376,7 @@
             </view>
           </view>
         </view>
+        
         <ProductWindow
           v-on:changeFun="changeFun"
           :attr="attr"
@@ -1105,6 +1106,7 @@ export default {
       if (typeof opt !== "object") opt = {};
       let action = opt.action || "";
       let value = opt.value === undefined ? "" : opt.value;
+      this.cart_num = 1
       this[action] && this[action](value);
     },