chore(package): update np to version 5.1.1

Closes #134

Author: greenkeeper[bot]

package.json

@@ -111,7 +111,7 @@
     "loadtest": "2.3.0",
     "mkdirp": "0.5.1",
     "mocha": "4.0.1",
-    "np": "2.16.1",
+    "np": "5.1.1",
     "npm-run-all": "4.1.1",
     "nsp": "3.1.0",
     "nyc": "11.3.0",