Lock version of HHVM to 3.1.0
Lock version of HHVM to 3.1.0

eduardofelipevieira/cursodev,eduardofelipevieira/cursodev,oddevan/heroku-wp,benmcntsh/fortnite-builder,xyu/heroku-wp,eduardofelipevieira/cursodev,oddevan/heroku-wp,xyu/heroku-wp,benmcntsh/fortnite-builder,jorgeas80/heroku-wp,xyu/heroku-wp,jorgeas80/heroku-wp,jorgeas80/heroku-wp,benmcntsh/fortnite-builder,oddevan/heroku-wp