typo in Documentation/react-scripts/on-ci-server/travis

Created by: zeel

I am using travis as my CI server and as per README( link ) used following script for .travis.yml file

language: node_js
node_js:
  - 6
cache:
  directories:
    - node_modules
script:
  - npm test
  - npm run build

The problem is with the order of commands. When running tests, it won't be able to find .css files as they are created in npm run build step.

I think following would be correct .travis.yml file.

language: node_js
node_js:
  - 6
cache:
  directories:
    - node_modules
script:
  - npm run build
  - npm test

Let me know if I can open PR for this.