message: Configure travis to update yarn.lock files
  for greenkeeper PRs
diff: @@ -7,3 +7,8 @@ node_js:
  - "4"
  before_install:
  - sudo sysctl fs.inotify.max_user_watches=524288
  + - yarn global add greenkeeper-lockfile@1
  +before_script:
  + - greenkeeper-lockfile-update
  +after_script:
  + - greenkeeper-lockfile-upload
  