chore(package): update engine.io-client to version 1.6.8
chore(package): update engine.io-client to version 1.6.8

http://greenkeeper.io/
Anup-Allamsetty/pure,scrollback/pure,Anup-Allamsetty/pure,Anup-Allamsetty/pure,scrollback/pure,belng/pure,scrollback/pure,Anup-Allamsetty/pure,belng/pure,belng/pure,scrollback/pure,belng/pure