tcl/board: add st_nucleo_g0.cfg to cover known STM32G0 NUCLEO boards

tcl/board: add st_nucleo_g0.cfg to cover known STM32G0 NUCLEO boards

known boards are NUCLEO-G031K8, NUCLEO-G070RB, NUCLEO-G071RB

note: this work safely with STM32G0316-DISCO, STM32G071B-DISCO
      and STM32G081B-EVAL

Change-Id: I483b6f44409228cd8c2c97b3c560927d1645c517
Signed-off-by: Tarek BOCHKATI <tarek.bouchkati@gmail.com>
Reviewed-on: https://review.openocd.org/c/openocd/+/5483
Reviewed-by: Andreas Bolsch <hyphen0break@gmail.com>
Reviewed-by: Antonio Borneo <borneo.antonio@gmail.com>
Tested-by: jenkins