HomeMaticHomeKitLuxMeterService.js:42 -> TypeError: newValue.toFixed is not a function
In [HomeMaticHomeKitLuxMeterService.js:42](https://github.com/thkl/homebridge-homematic/blob/7a42f7bf13910bbde8e58b4a21e937f497b091d5/ChannelServices/HomeMaticHomeKitLuxMeterService.js#L42) :
`var fvalue = newValue.toFixed(2)`
throws "_TypeError: newValue.toFixed is not a function_".

Changing it to
`var fvalue = parseFloat(newValue).toFixed(2);`
works.