fix(package): update mqtt to version 3.0.1

Closes #24

Author: greenkeeper[bot]

package.json

@@ -19,7 +19,7 @@
   "homepage": "https://github.com/msgflo/msgflo-project#readme",
   "dependencies": {
     "fbp-protocol-healthcheck": "^1.0.0",
-    "mqtt": "^2.9.0",
+    "mqtt": "^3.0.1",
     "msgflo": "^0.12.0",
     "msgflo-nodejs": "^0.11.0"
   },