chore(package): update node-sass to version 4.2.0
chore(package): update node-sass to version 4.2.0

https://greenkeeper.io/

lmorchard/testpilot,mozilla/idea-town-server,6a68/idea-town,meandavejustice/testpilot,flodolo/testpilot,fzzzy/testpilot,mozilla/idea-town-server,mozilla/idea-town-server,lmorchard/idea-town-server,lmorchard/idea-town,lmorchard/idea-town-server,lmorchard/testpilot,dannycoates/testpilot,6a68/testpilot,lmorchard/testpilot,dannycoates/testpilot,6a68/testpilot,mozilla/idea-town-server,lmorchard/idea-town,6a68/idea-town,meandavejustice/testpilot,mozilla/idea-town,6a68/testpilot,6a68/testpilot,flodolo/testpilot,mathjazz/testpilot,fzzzy/testpilot,mathjazz/testpilot,mathjazz/testpilot,fzzzy/testpilot,mathjazz/testpilot,chuckharmston/testpilot,6a68/idea-town,dannycoates/testpilot,flodolo/testpilot,6a68/idea-town,lmorchard/idea-town,mozilla/idea-town,mozilla/idea-town,chuckharmston/testpilot,chuckharmston/testpilot,lmorchard/idea-town,fzzzy/testpilot,dannycoates/testpilot,meandavejustice/testpilot,lmorchard/idea-town-server,flodolo/testpilot,meandavejustice/testpilot,lmorchard/idea-town-server,lmorchard/testpilot,mozilla/idea-town,chuckharmston/testpilot