Upgrade to stylus-loader 2.0, along with peer stylus 0.54
Upgrade to stylus-loader 2.0, along with peer stylus 0.54

This was needed to sidestep a weird build issue with stylus 0.52
(https://github.com/stylus/stylus/issues/2176), which was being used as a
dependency of stylus-loader 1.5.

Kitware/candela,Kitware/candela,Kitware/candela,Kitware/candela,Kitware/candela