load json from uri as Template Variable

[personball]

Is your feature request related to a problem? Please describe.

无需将 swagger.json 文件下载到本地再加载作为模板变量，可以少同步一份文件，也避免忘记更新本地的swagger.json。

Describe the solution you'd like

直接发起http请求获取 swagger.json 内容

优先级：低