Fixes broken link in contributing doc.
Fixes broken link in contributing doc.

lenvanessen/bolt,bolt/bolt,Intendit/bolt,Intendit/bolt,romulo1984/bolt,electrolinux/bolt,nikgo/bolt,electrolinux/bolt,nikgo/bolt,bolt/bolt,lenvanessen/bolt,lenvanessen/bolt,bolt/bolt,nikgo/bolt,Intendit/bolt,GawainLynch/bolt,electrolinux/bolt,GawainLynch/bolt,romulo1984/bolt,GawainLynch/bolt,romulo1984/bolt,romulo1984/bolt,GawainLynch/bolt,lenvanessen/bolt,bolt/bolt,nikgo/bolt,electrolinux/bolt,Intendit/bolt