chore(package): update lint-staged to version 6.0.0

Closes #28

Author: greenkeeper[bot]

package.json

@@ -15,7 +15,7 @@
     "@types/node": "^8.0.16",
     "ava": "^0.23.0",
     "husky": "^0.14.3",
-    "lint-staged": "^4.0.2",
+    "lint-staged": "^6.0.0",
     "prettier": "^1.5.3",
     "serverless-plugin-typescript": "^1.0.0",
     "serverless-apigwy-binary": "^0.1.0"