fix(package): update bluebird to version 3.7.0

Closes #48

Author: greenkeeper[bot]

package.json

@@ -33,7 +33,7 @@
     "homepage": "https://github.com/nodefluent/kafka-connect#readme",
     "dependencies": {
         "async": "~2.6.2",
-        "bluebird": "~3.5.4",
+        "bluebird": "~3.7.0",
         "body-parser": "~1.19.0",
         "debug": "~4.1.1",
         "express": "~4.16.4",