that.log.error is not a function, shuts down Homebridge
this error sequence killed off Homebridge. I restarted HB and interrogated the plugin via Siri, no issues.

```
homebridge@1.0.4
homebridge-weather-plus@3.2.0
npm@6.14.5


[5/10/2020, 7:43:47 AM] TypeError: that.log.error is not a function
at WundergroundAPI.<anonymous> (/usr/local/lib/node_modules/homebridge-weather-plus/apis/weatherunderground.js:66:14)
at self.callback (/usr/local/lib/node_modules/homebridge-weather-plus/node_modules/request/request.js:185:22)
at Request.emit (events.js:210:5)
at Request.onRequestError (/usr/local/lib/node_modules/homebridge-weather-plus/node_modules/request/request.js:877:8)
at ClientRequest.emit (events.js:210:5)
at TLSSocket.socketErrorListener (_http_client.js:406:9)
at TLSSocket.emit (events.js:210:5)
at emitErrorNT (internal/streams/destroy.js:92:8)
at emitErrorAndCloseNT (internal/streams/destroy.js:60:3)
at processTicksAndRejections (internal/process/task_queues.js:80:21)
[5/10/2020, 7:43:47 AM] Got SIGTERM, shutting down Homebridge...
```