Merge pull request #588 from oauthjs/renovate/bluebird-3.x

Update dependency bluebird to v3.7.2

Author: thomseddon

package.json

@@ -18,7 +18,7 @@
   "main": "index.js",
   "dependencies": {
     "basic-auth": "1.1.0",
-    "bluebird": "3.5.0",
+    "bluebird": "3.7.2",
     "lodash": "4.17.4",
     "promisify-any": "2.0.1",
     "statuses": "1.3.1",