仓库管理新增新采购相关 RPC 接口

src/Service/Interfaces/Store/StorePurchaseServiceInterface.php

+<?php
+/**
+ * Created by PhpStorm.
+ * User: 王源
+ * Date: 2020/3/16
+ * Time: 15:07
+ */
+
+namespace Meibuyu\Rpc\Service\Interfaces\Store;
+
+interface StorePurchaseServiceInterface
+{
+    /**
+     * 创建对应的退货单, $params 数组结构如下：
+     *  [
+    'source_type'   => '',          //来源类型，默认为采购
+    'source_no'     => '',          //来源单号，比如来源是采购就是采购单号
+    'batch_no'      => '',          //对应的批次号
+    'sku'           => '',          //sku
+    'purchased_cnt' => 0,           //购买量
+    'returns_cnt'   => 0,           //退货数量
+    ];
+     * @param array $params
+     * @return array
+     * [
+    'msg' => '退货成功',
+    'code'=> 200,                       //响应码
+    'data' => ['id' => 退货 ID]          //返回的数据，id 为对应的退货 ID
+    ];
+     * @throws
+     */
+    public function createReturns(array $params): array;
+}