执行 truffle unbox pet-shop 报错，因为无法连接raw.githubusercontent.com，需要翻墙或者配置本地host文件
解决方案：
1、通过 https://www.ipaddress.com 查询 raw.githubusercontent.com 的 地址。
2、配置host文件 C:\Windows\System32\drivers\etc\host 增加以下内容
199.232.68.133 raw.githubusercontent.com
√ Preparing to download box × Downloading Unbox failed! RequestError: Error: getaddrinfo ENOENT raw.githubusercontent.com raw.githubusercontent.com:443 at new RequestError (C:\Program Files\Node\node_modules\truffle\build\webpack:\node_modules\request-promise-core\lib\errors.js:14:1) at Request.plumbing.callback (C:\Program Files\Node\node_modules\truffle\build\webpack:\node_modules\request-promise-core\lib\plumbing.js:87:1) at Request.RP$callback [as _callback] (C:\Program Files\Node\node_modules\truffle\build\webpack:\node_modules\request-promise-core\lib\plumbing.js:46:1) at self.callback (C:\Program Files\Node\node_modules\truffle\build\webpack:\node_modules\request\request.js:185:1) at Request.emit (events.js:198:13) at Request.onRequestError (C:\Program Files\Node\node_modules\truffle\build\webpack:\node_modules\request\request.js:881:1) at ClientRequest.emit (events.js:198:13) at TLSSocket.socketErrorListener (_http_client.js:401:9) at TLSSocket.emit (events.js:198:13) at emitErrorNT (internal/streams/destroy.js:91:8) at emitErrorAndCloseNT (internal/streams/destroy.js:59:3) at process._tickCallback (internal/process/next_tick.js:63:19) Truffle v5.1.32 (core: 5.1.32) Node v10.20.0
