Migrate to dep (#3972)

* Update makefile to use dep

* Migrate to dep

* Fix some deps

* Try to find a better version for golang.org/x/net

* Try to find a better version for golang.org/x/oauth2

vendor/github.com/lunny/dingtalk_webhook/README.md

@@ -1,18 +0,0 @@
-# 非官方 Dingtalk webhook Golang SDK
-
-## 此工程仅封装了 Dingtalk 的 webhook 部分的请求
-
-## 使用
-
-首先在dingtalk中创建一个机器人，将accessToken拷贝出来，然后执行下面方法即可
-
-```Go
-webhook := dingtalk.Webhook(accessToken)
-webhook.SendTextMsg("这是一个没有AT的文本消息", false)
-```
-
-## License
-
-This project is licensed under the MIT License.
-See the [LICENSE](https://github.com/lunny/webhook_dingtalk/blob/master/LICENSE) file
-for the full license text.