Ensure npm@5 in travis

sfrdmn · sfrdmn · commit 8ff5a259b1da · 2017-10-14T14:56:06.000+02:00
diff --git a/.travis.yml b/.travis.yml
@@ -2,6 +2,7 @@ language: ruby
 before_install:
 - curl -o- https://raw.githubusercontent.com/creationix/nvm/v0.33.5/install.sh | bash
 - nvm install 6
+- npm install npm@5 -g
 - eval `ssh-agent -s`
 - gem update --system
 before_script:
