Added Studio Frenetic to companies using Gitlab

I know this is not the source code for the actual website, but if you're interested in adding us as a company using Gitlab, we'll be very grateful. 

We've made a couple of contributions in the past and surely we will continue to do so because Gitlab is so freakin' awesome. Thanks! :+1: 

Signed-off-by: Martin Bastien <martin.bastien@studiofrenetic.com>