Add GL73 to compatible devices

[bwu62]

Thought I should open a separate ticket for this for record keeping. I just installed this on my GL73 9SDK-413 and it works like a charm on the default (GE63) as well as several other settings (GE73, GS73, GL63, etc.)

Running the new Ubuntu 20.04 LTS by the way; lsusb shows my keyboard device as:

Bus 001 Device 003:
ID 1038:1122
SteelSeries ApS SteelSeries KLC

Let me know if you want me to run any additional tests for you to check compatibility, but otherwise I think you can officially add this to the list of supported devices.

good job on this project, excellent stuff 👍