Markdown inline html sanitization , use of awsomefont in markdown rendering

I would like to use awsomefont incons in the markdown for README.mb files for exemple, putting some inline html in the markdown like this <i class="fa fa-gitlab" aria-hidden="true"></i>, for example.

The <i> tag is accepted but the class attribute is remove by sanitization

When i live edit the rendering with by browser inspector to add the class, the icon is displayed !

I wouldlike to whitlist the class attribute in the markdown sanitization

anyone can help me ?