chore(package): update nsp to version 3.1.0

Closes #39

Author: greenkeeper[bot]

package.json

@@ -45,7 +45,7 @@
     "jsdoc": "^3.4.3",
     "mocha": "^3.4.2",
     "npm-install-peers": "^1.1.0",
-    "nsp": "^2.6.3",
+    "nsp": "^3.1.0",
     "nyc": "^11.0.3",
     "semantic-release": "^6.3.6",
     "semantic-release-cli": "^3.0.3",