Request to https://api.ring.com/clients_api/dings/active failed:
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# Bug Report

### Describe the Bug
<!-- ✍️edit: --> The system does not refresh the token after ~1 hour or so. Error message:

Request to https://api.ring.com/clients_api/dings/active failed:
[8/2/2021, 8:43:07 AM] [Ring] Error: Refresh token is not valid.  Unable to authenticate with Ring servers.  See https://github.com/dgreif/ring/wiki/Refresh-Tokens
    at RingRestClient.getGrantData (/usr/local/lib/node_modules/homebridge-ring/lib/api/rest-client.js:93:15)
    at RingRestClient.<anonymous> (/usr/local/lib/node_modules/homebridge-ring/lib/api/rest-client.js:97:36)
    at Generator.next (<anonymous>)
    at /usr/local/lib/node_modules/homebridge-ring/lib/api/rest-client.js:8:71
    at new Promise (<anonymous>)
    at __awaiter (/usr/local/lib/node_modules/homebridge-ring/lib/api/rest-client.js:4:12)
    at RingRestClient.getAuth (/usr/local/lib/node_modules/homebridge-ring/lib/api/rest-client.js:96:16)
    at RingRestClient.<anonymous> (/usr/local/lib/node_modules/homebridge-ring/lib/api/rest-client.js:121:33)
    at Generator.throw (<anonymous>)
    at rejected (/usr/local/lib/node_modules/homebridge-ring/lib/api/rest-client.js:6:65) "

 {"error":"Unauthorized","status_code":401}

### To Reproduce
Steps to reproduce the behavior:
 - Start Homebridge
 - Attempt to ...
 - See error

### Expected behavior
<!-- ✍️edit: --> A clear and concise description of what you expected to happen.


### Screenshots/Logs
<!-- ✍️edit: --> If applicable, add screenshots and log output to help explain your problem.

### Additional context
<!-- ✍️edit: --> Add any other context about the problem here.

### Homebridge Ring Config
Post homebridge-ring platform config  _without sensitive information_
```

HIGHLIGHT THIS TEXT AND POST CONFIG HERE
DO NOT INCLUDE YOUR REFRESH TOKEN OR EMAIL/PASSWORD (replace them with xxx)

```

### Environment
<!-- ✍️edit: -->
 - OS: [e.g. MacOS]
 - Node.js: [e.g. 12.14.1] <!-- run `node -v` to get current version -->
 - NPM: [e.g 6.13.4] <!-- run `npm -v` to get current version -->
 - homebridge-ring: [e.g 6.0.3]
 - homebridge: [e.g. v19.0.0]
 - hoobs: [ N/A]
