message: add hack to install fs-extra on Travis
diff: @@ -7,6 +7,10 @@ cache:
  # cache jest intermediary files between builds
  - $(jq -r .jest.cacheDirectory package.json)
  +# XXX remove this after merging
  +before_script:
  + - npm i fs-extra
  +
  script:
  - npm run lint
  # see <https://github.com/facebook/jest/issues/3855> for more info
  