Update lint-staged to the latest version 🚀 (#1019)

* chore(package): update lint-staged to version 7.0.0

* chore: update yarn.lock

Author: greenkeeper[bot]

package.json

@@ -77,7 +77,7 @@
     "husky": "^0.14.3",
     "jest": "^22.1.4",
     "json-schema": "0.2.3",
-    "lint-staged": "^6.0.1",
+    "lint-staged": "^7.0.0",
     "mock-fs": "^4.4.2",
     "p-event": "^1.3.0",
     "prettier": "^1.10.2",