Update json.loads line for python 3.5
Update json.loads line for python 3.5

Running the script inside a docker container with python 3.5 throws an "TypeError: the JSON object must be str, not 'bytes'".

Fixed it by decoding downloaded json to utf-8
dresden-elektronik/deconz-rest-plugin,dresden-elektronik/deconz-rest-plugin,dresden-elektronik/deconz-rest-plugin,dresden-elektronik/deconz-rest-plugin,dresden-elektronik/deconz-rest-plugin