chore(package): update phantomjs-prebuilt to version 2.1.8
chore(package): update phantomjs-prebuilt to version 2.1.8

https://greenkeeper.io/
fshchudlo/e2e4,eastbanctechru/e2e4,fshchudlo/e2e4,fshchudlo/e2e4,eastbanctechru/e2e4,eastbanctechru/e2e4