language: node_js
node_js:
  - stable
  - "6"
  - "4"
branches:
  only:
    - master
sudo: false
script: npm test

language: node_js
node_js:
  - "10"
  - "8"
  - "6"
  - "4"
script:
  - npm test

Add Node versions 8 & 10
test(ci): Add Node versions 8 & 10
