chore(package): update lint-staged to version 4.0.0 (#470)

Author: greenkeeper[bot]

package.json

@@ -33,7 +33,7 @@
  "eslint-plugin-flowtype": "^2.25.0",
  "eslint-plugin-prettier": "^2.1.2",
  "husky": "^0.13.2",
- "lint-staged": "^3.3.1",
+ "lint-staged": "^4.0.0",
  "nyc": "^11.0.1",
  "prettier": "^1.2.2",
  "react": "^15.1.0",