Homebridge exits when loading homebridge-ring config
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# Bug Report

### Describe the Bug
Previously working Homebridge install is refusing to start completely, and exits on startup
This only occurs when the Ring platform is present in the Homebridge config.

### To Reproduce
Steps to reproduce the behavior:
 - Start Homebridge with Ring config present

### Expected behavior
Homebridge starts cleanly

### Screenshots/Logs
https://gist.github.com/ceeeekay/b1abf28eade1a1b6890a13317e0e9b84

### Additional context
I am unsure whether this issue is related to homebridge-ring, or some other underlying Homebridge/OS issue.
I updated homebridge-config-ui-x and homebridge-ring to the lastest versions, and have had this issue since restarting the Homebridge service after the update.
It was previously working fine with the current config (and tested again against a known good backup). 
I've also downgraded homebridge-ring to 9.0.0 but the problem persists.
* Removing all other plugin configs, and leaving the Ring config present still exhibits this issue.
* Removing only the ring config and leaving all other plugin configs, and Homebridge starts successfully.
This makes me suspect the issue is something related to homebridge-ring, but I'm not 100% sure that's the case.

### Homebridge Ring Config
https://gist.github.com/ceeeekay/987ca27c0fa0675e1c41099759ed7c80

### Environment
 - OS: Ubuntu
 - Node.js: v14.0.0 
 - NPM: 6.14.4
 - homebridge-ring: 9.1.1
 - homebridge: 1.1.0
 - hoobs: N/A
