fix(package): update bluebird to version 3.7.2

Closes #11

Author: greenkeeper[bot]

package.json

@@ -11,7 +11,7 @@
     "test": "jest"
   },
   "dependencies": {
-    "bluebird": "~3.5.0",
+    "bluebird": "~3.7.2",
     "sliced": "1.0.1",
     "uuid": "~3.1.0"
   },