This builds the keyboard firmware using zmk-nix.
The miryoku_zmk config is pulled in from manna-harbour/miryoku_zmk, but
slightly patched to add support for RALT and quick-tap.
Change-Id: I91efbbd789526cce7f086f367c7bccb7857b06e6
Reviewed-on: https://cl.tvl.fyi/c/depot/+/12695
Tested-by: BuildkiteCI
Reviewed-by: flokli <flokli@flokli.de>
Autosubmit: flokli <flokli@flokli.de>