Homebridge-TPLink-Smarthome 6.4.0 Causes Crashing for HOOBS 3.3.5
<!-- Provide a general summary in the Title above -->
It appears that v6.4.0 of this plugin is incompatible with the current release version of HOOBS despite being "HOOBS Certified". Based on the description provided below, I suspect that this version of the plugin requires a more current version of homebridge (1.3.3) than is included in the current HOOBS distribution. This version of the plugin causes the HOOBS bridge service to stop when the plugin initializes. Can the plugin be updated to check for a homebridge version lower than 1.3.1 and avoid use of 1.3.3-only features to try and avoid the crashing?

I am also reporting this issue to HOOBS to try and encourage them to (1) update ASAP to the latest version of homebridge, and (2) allow end-users to download and install prior versions of plugins to avoid these kinds of issues in future.

### Expected Behavior
BUG: Plugin should initialize without error and allow HOOBS/homebridge service to start.

### Current Behavior
BUG: Plugin attempts to initialize but fails; HOOBS/homebrdge service stops.

### Steps to Reproduce (for bugs)
1. Install plugin into an installation of HOOBS 3.3.5
2. View log in Dashboard to see the following:
```
5/22/2021, 11:13:25 PM [TplinkSmarthome] Initializing TplinkSmarthome platform...
5/22/2021, 11:13:25 PM [TplinkSmarthome] homebridge-tplink-smarthome v6.4.0, node v12.19.0, homebridge v1.3.3, api v2.7
```

### Versions
<!-- Please run commands and include versions below. -->
- **Node**:       `node --version` - v12.19.0
- **HOOBS**:  `hoobs --version` - 3.3.5
- **Homebridge**: `homebridge --version`. (Per HOOBS 3.3.5 release notes, it is built on Homebridge 1.3.1)
- **OS**:         Raspbian 10

### Configuration
<!-- Please include the TplinkSmarthome platform section of your config.json file.
Paste between the the two ``` lines below.
-->
```json
        {
            "platform": "TplinkSmarthome",
            "plugin_map": {
                "plugin_name": "homebridge-tplink-smarthome"
            }
        }
```

### Homebridge Log / Command Output
<!-- Paste relevant output between the two ``` lines below
  - Remove any sensitive information, passwords, etc.
  - If output is long:
    - Please extract only the relevant portions if possible (remove other plugin's output, etc)
    - Consider creating a gist, etc
  - However, please include the beginning of the log where the homebridge initialization happens if possible
-->
```
5/22/2021, 11:13:25 PM [TplinkSmarthome] Initializing TplinkSmarthome platform...
5/22/2021, 11:13:25 PM [TplinkSmarthome] homebridge-tplink-smarthome v6.4.0, node v12.19.0, homebridge v1.3.3, api v2.7
```
