chore(package): update eslint-plugin-node to version 6.0.0 (#22)

Author: greenkeeper[bot]

package.json

@@ -51,7 +51,7 @@
     "eslint-plugin-import": "^2.8.0",
     "eslint-plugin-mocha": "^4.10.1",
     "eslint-plugin-mocha-only": "0.0.3",
-    "eslint-plugin-node": "^5.2.0",
+    "eslint-plugin-node": "^6.0.0",
     "eslint-plugin-promise": "^3.6.0",
     "istanbul": "^0.4.3",
     "jsdoc": "^3.5.5",