chore: use david-dm dependencies badge

bufferoverflow · web-flow · commit 8cecda2e00dc · 2018-01-12T20:16:55.000+01:00
diff --git a/README.md b/README.md
@@ -7,6 +7,7 @@ Mosca&nbsp;&nbsp;&nbsp;[![Build Status](https://travis-ci.org/mcollina/mosca.svg
 
 [![NPM](https://nodei.co/npm-dl/mosca.png)](https://nodei.co/npm/mosca/)
 
+[![dependencies Status](https://david-dm.org/mcollina/mosca/status.svg)](https://david-dm.org/mcollina/mosca)
 ## About
 
 #### Mosca is a node.js mqtt broker, which can be used:
