chore(travis): preserve `npm install` (#151)
chore(travis): preserve `npm install` (#151)

The default `install` script on Travis is now `npm ci` instead of `npm install`, which causes `package-lock.json` and `greenkeeper` to be incompatible, see the travis build in #149 for example.
alexjoverm/tslint-config-prettier,alexjoverm/tslint-config-prettier