Upgrade rumqttc (#19)

* Upgrade rumqttc

* Update CHANGELOG.md

* fmt

Author: mikekap

CHANGELOG.md

@@ -2,6 +2,7 @@
  - Add support for older version of firmware that doesn't report Gang data.
  - Add support for STRING-based properties & discovery of STRING-based On_Off switches.
  - Add support for UInt16/32-based properties in parsing.
+ - Upgrade the mqtt client to attempt fixing reconnection issues (disconnects from the MQTT server would sometimes fail to retry connecting).
 
 ## 0.1.3
  - Report errors more readably better when things fail