Bump versions of the dependencies:
- node: v8.9.0 LTS;
- homebridge: v0.4.31;
- deCONZ: v2.4.85;
- request: v2.83.0.
Note that you need to uninstall/re-install homebridge after upgrading from Node v6.x (or 7.x) to Node v8.x, to force re-compilation of the mdns package.
Support Xiaomi WXKG02LM switch, see #203 and dresden-elektronik/deconz-rest-plugin#165.