Update config.md

Field is "healthy", not "health"

docs/config.md

@@ -1180,10 +1180,10 @@ and [here](https://easyengine.io/tutorials/nginx/block-wp-login-php-bruteforce-a
 
 ## Health checks
 A preliminary health check API endpoint is exposed at `/v1/health`. The endpoint returns a `json` response in the format shown below.
-If a non-200 HTTP status code is returned or if the returned `health` field is `false` the ntfy service should be considered as unhealthy.
+If a non-200 HTTP status code is returned or if the returned `healthy` field is `false` the ntfy service should be considered as unhealthy.
 
 ```json
-{"health":true}
+{"healthy":true}
 ```
 
 See [Installation for Docker](install.md#docker) for an example of how this could be used in a `docker-compose` environment.