language: node_js
node_js:
  - "7.8.0"
before_install:
  - npm i -g npm@5.6.0
cache:
  directories:
    - node_modules

language: node_js
node_js:
  - '8'
before_install:
  - npm i -g npm@5.6.0
cache:
  directories:
    - node_modules

Upgrade node version in Travis CI
Upgrade node version in Travis CI
