fix(package): update bluebird to version 3.7.0

Closes #50

Author: greenkeeper[bot]

package.json

@@ -21,7 +21,7 @@
     "plugin"
   ],
   "dependencies": {
-    "bluebird": "3.5.1",
+    "bluebird": "3.7.0",
     "body-parser": "1.18.2",
     "cli-color": "1.2.0",
     "compression": "1.7.1",