chore scss: don't use deprecated bourbon box-sizing mixin
chore scss: don't use deprecated bourbon box-sizing mixin

cupceavictor/lumX,terradatum/lumX,hinablue/lumX,lumapps/lumX,b-cuts/lumX,lumapps/lumX,jefvel/lumX,bijeeshtk/lumx,terradatum/lumX,terradatum/lumX,hinablue/lumX,hinablue/lumX,jefvel/lumX,cupceavictor/lumX,lumapps/lumX,bijeeshtk/lumx,b-cuts/lumX,bijeeshtk/lumx,jefvel/lumX,cupceavictor/lumX,jefvel/lumX,b-cuts/lumX,bijeeshtk/lumx,terradatum/lumX,ezzye/write-to-be-heard,ezzye/write-to-be-heard,hinablue/lumX,lumapps/lumX,ezzye/write-to-be-heard,b-cuts/lumX,ezzye/write-to-be-heard,cupceavictor/lumX