change in Hue API >> discovery of hue bridge

[thojust]

I was unable to get working on mac os 10.13.6 or Linux Mint 20.1 but I was able to get the vagrant vm running,(thanks johnpc for the solution). Had to tweak HueBroker.hs to include the updated url for UPnP discovery. It is now line 42: let brokerServerURL = "https://discovery.meethue.com/"