Battery level 0% in Home application[Bug] 
I have successfully integrated a Heimann smoke sensor with zigbee2mqtt and this package in my homebridge. The Heimann smoke sensor is a supported device in the zigbee2mqtt database. However, I found that the battery level was shown as 0% in my Apple Home app. As this sensor does actually report its battery level I decided to have a look at the zigbee2mqtt log to check the name of the parameter. I found that this sensor reports its battery level with 'battery_level' instead of 'battery'. Is this why I cannot read out the battery level? And; how can I fix this?

I am currently using the latest version of homebridge, homebridge-z2m, and zigbee2mqtt.
