Seeed XIAO RA4M1 / XIAORA4M1 support

[EtoTen]

Could you please add XIAORA4M1 as a board variant? It is divergent from an UNO and the other boards in pin definition. Seeed already developed the Arduino-core with XIAORA4M1 support (./variants)

When I modified this platform locally to include the core from Seeed the project still compiled.
https://files.seeedstudio.com/arduino/core/renesas/ArduinoCore-renesas-1.2.0.tar.bz2