Add update instructions for removed MQTT System Broker (#1380)

* Instruct users to replace their things
* Remove mqttbroker.config

See also:

* openhab/openhab-addons#12157
* openhab/openhab-core#2842

Signed-off-by: Wouter Born <[email protected]>

distributions/openhab/src/main/resources/bin/update.lst

@@ -63,6 +63,7 @@ ALERT;Sony Projector Binding: The type of the channel 'power' was updated. You m
 [3.3.0]
 ALERT;Daikin Binding: The channel 'specialmode-powerful' has been removed, and a r/w channel 'streamer' added. The channel 'specialmode' changed to read/write to control eco/powerful mode.
 ALERT;DanfossAirUnit Binding: The type of the channel 'humidity' was updated. You may need to remove and create your things again in case your things were previously created using UI and you want to use this channel.
+ALERT;MQTT Binding: Support for the MQTT System Broker has been removed. Replace 'mqtt:systemBroker' things with 'mqtt:broker' things.
 ALERT;OmniLink Binding: The channel 'sysdate' has been renamed to 'system_date'.
 ALERT;OpenthermGateway Binding: The 'otgw' Thing has been removed and split into a new 'openthermgateway' Bridge, and a new 'boiler' Thing. You will need to change your Thing and respective Item definitions.
 ALERT;RFXCOM Binding: The channel 'fanSpeed' of 'fan_lucci_dc' and 'fan_novy' has been renamed to 'fanSpeedControl', and 'fan_lucci_dc' has a new numeric channel 'fanSpeed'. You may need to remove and create your things again.
@@ -160,3 +161,6 @@ DELETEDIR;$OPENHAB_USERDATA/config/com/eclipsesource
 MOVE;$OPENHAB_USERDATA/config/org/openhab/io/metrics/MetricsRestController.config;$OPENHAB_USERDATA/config/org/openhab/metrics.config
 REPLACE;org.openhab.io.metrics.MetricsRestController;org.openhab.metrics;$OPENHAB_USERDATA/config/org/openhab/metrics.config
 DELETEDIR;$OPENHAB_USERDATA/config/org/openhab/io/metrics
+
+[3.3.0]
+DELETE;$OPENHAB_USERDATA/config/org/openhab/mqttbroker.config