Do some upgrades.

[an-tao]

1. Fix an issue when sending emails;
2. Add the isHttp flag to send emails in HTML format;

@ihmc3jn09hk I changed some thing of this plugin when using it, please check it out, note that I used local clang-format configuration to format the source code, you could format it with your tool to reduce the differences introduced by formatting.

[ihmc3jn09hk]

1. Fix an issue when sending emails;
2. Add the isHttp flag to send emails in HTML format;

@ihmc3jn09hk I changed some thing of this plugin when using it, please check it out, note that I used local clang-format configuration to format the source code, you could format it with your tool to reduce the differences introduced by formatting.

Hey @an-tao , how you doing ?
Terribly sorry for the late reply. I am glad that the plugin is contributing.