"sortable" attribute value is removed

I am using an attribute named `sortable` in my AngularJS templates the following way:
`sortable="name"`, `sortable="age"`, ...
The problem is that when I build the application, grunt-angular-templates removes the sortable attribute value. So, `sortable="name"` becomes `sortable`.
I have been able to get around this issue by using `data-sortable` instead but it would be nice if it is fixed so that other people don't waste their time in the future trying to understand why their Grunt built application is not working correctly.