Excessive number of DNS requests
I have homebridge running through my personal DNS server and have noticed a major uptick in DNS requests since I setup homebridge-nest-cam.  I am seeing ~100k requests/day going to (each).

nexusapi-us1.camera.home.nest.com
webapi.camera.home.nest.com

That by farm exceeds any other requests I have at home by a factor of 10.  Though it's not really hurting anything, I know for a lot of users depending on their ISP, DNS requests like that could cause them to get blocked for short times as it could be considered an attack (Plus it's just pure inefficient)

I current run 4 Cams (1 IQ Outdoor, 1 Outdoor, 1 Indoor and a  Hello Cam)

Include with your bug report this version info:
```
node --version
v12.16.3
homebridge --version
1.1.0
homebridge-nest-cam v2.3.3

docker --version
Docker version 19.03.9, build 9d988398e7
```

