Add PID 1209:C64B for Pico USB Keyboard

[do2mad]

Requesting PID 0xC64B for Pico USB Keyboard: https://github.com/do2mad/pico-usb-keyboard

• Open-source firmware, MIT license (LICENSE file in the repository)
• Hardware is a stock Raspberry Pi Pico 2 W - there are no custom PCB files; the firmware is the whole project
• USB class: standard HID boot keyboard
• Currently uses the test PID 1209:0001, will switch to the assigned PID

Thank you!

[cnlohr]

MIT license for code, uses Pi Pico W, no additional hardware needed. Designs for case and all details included. Project all written in C.