travis: include node 8.0.0 (#2395)
travis: include node 8.0.0 (#2395)


umaar/lighthouse,tkadlec/lighthouse,mixed/lighthouse,deepanjanroy/lighthouse,wardpeet/lighthouse,umaar/lighthouse,wardpeet/lighthouse,tkadlec/lighthouse,GoogleChrome/lighthouse,arturmiz/lighthouse,tkadlec/lighthouse,deepanjanroy/lighthouse,mixed/lighthouse,arturmiz/lighthouse,arturmiz/lighthouse,umaar/lighthouse,GoogleChrome/lighthouse,umaar/lighthouse,GoogleChrome/lighthouse,tkadlec/lighthouse,deepanjanroy/lighthouse,ev1stensberg/lighthouse,GoogleChrome/lighthouse,GoogleChrome/lighthouse,arturmiz/lighthouse,mixed/lighthouse,wardpeet/lighthouse,arturmiz/lighthouse,wardpeet/lighthouse,ev1stensberg/lighthouse,wardpeet/lighthouse,ev1stensberg/lighthouse,mixed/lighthouse,deepanjanroy/lighthouse,deepanjanroy/lighthouse,ev1stensberg/lighthouse