一，安装第三方库：$goget-ugithub.com/jordan-wright/emailgo:downloadinggithub.com/jordan-wright/emailv4.0.1-0.20210109023952-943e75fe5223+incompatiblego:addedgithub.com/jordan-wright/emailv4.0.1-0.20210109023952-943e75fe5223+incompatible二，代码：1,发送