chore(package): update ember-cli-sass to version 6.0.0
chore(package): update ember-cli-sass to version 6.0.0

https://greenkeeper.io/
jrjohnson/frontend,ilios/frontend,gabycampagna/frontend,ilios/frontend,thecoolestguy/frontend,dartajax/frontend,djvoa12/frontend,djvoa12/frontend,jrjohnson/frontend,dartajax/frontend,gboushey/frontend,thecoolestguy/frontend,gboushey/frontend,gabycampagna/frontend