Merge branch 'dtx_pay' into 'master'

Dtx pay

See merge request !7

src/Notify/WxNotify.php

@@ -144,6 +144,9 @@ class WxNotify extends NotifyStrategy
             'trade_state' => strtolower($data['return_code']),
             'channel' => Config::WX_CHARGE,
         ];
+        if (!empty($data['coupon_fee'])) {
+            $retData['coupon_fee'] = $data['coupon_fee'];
+        }
         if (!empty($data['sub_appid'])) {
             $retData['sub_appid'] = $data['sub_appid'];
         }