Unexpected token '>='
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### What issue do you have? Please be as thorough and explicit as possible.

I'm getting the following logs when trying to use your plugin:

```
[30/12/2020, 12:05:04] [eWeLink] Plugin [v3.18.1] initialised. Syncing with eWeLink...

[30/12/2020, 12:05:05] [eWeLink] *** Disabling plugin [v3.18.1] ***

[30/12/2020, 12:05:05] [eWeLink] Unexpected token '>='
```

### Details of your setup.
* Do you use Homebridge (with config-ui?) or HOOBS? 

Homebridge (with config-ui)


* Which version of Homebridge/HOOBS do you have?

1.1.6


* Which version of this plugin (homebridge-ewelink) do you have? Has the issue started since upgrading from a previous version?

v3.18.1
This is the first time using this plugin.

* Which eWeLink devices do you have that are causing issues? Please include product models if applicable.

SONOFF DW2-Wi-Fi

* Do you use your main eWeLink credentials or do you use a secondary eWeLink account for Homebridge?

I use the main ones


### Please paste any relevant logs below.
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```

```
