chore(package): update eslint-plugin-node to version 8.0.0

Closes #14

Author: greenkeeper[bot]

package.json

@@ -31,7 +31,7 @@
     "eslint": "^4.13.1",
     "eslint-config-standard": "^11.0.0",
     "eslint-plugin-import": "^2.8.0",
-    "eslint-plugin-node": "^6.0.0",
+    "eslint-plugin-node": "^8.0.0",
     "eslint-plugin-promise": "^3.6.0",
     "eslint-plugin-standard": "^3.0.1",
     "mocha": "^5.0.0",