Digest auth support
**Describe the bug**
Basic auth is not working

**Expected behavior**
When using the "auth" parameter for your plugin I still get 401 not authorized for each request. I was testing the same setup but with homebridge-http and its working all fine. I would prefer using your plugin though. Could you have a look into that?


**Version** 
 - homebridge: homebridge@0.4.45
 - homebridge-http-switch: homebridge-http-switch@0.5.9

**Configuration**
{
    "accessories": [
        {
          "accessory": "HTTP-SWITCH",
          "name": "Switch",
          "switchType": "stateful",
          "auth": {
               "username": "myUsername",
               "password": "myPassword"
          },         
          "onUrl": "http://localhost/api/switchOn",
          "offUrl": "http://localhost/api/switchOff",
          
          "statusUrl": "http://localhost/api/switchStatus"
        }   
    ]
}

