run_archiso.sh: qemu's short-form boolean option 'readonly' is deprecated

With qemu 6.0.0-1, running run_archiso.sh produces:

qemu-system-x86_64: -drive if=pflash,format=raw,unit=0,file=/usr/share/edk2-ovmf/x64/OVMF_CODE.fd,readonly: warning: short-form boolean option 'readonly' deprecated
Please use readonly=on instead

To upload designs, you'll need to enable LFS and have an admin enable hashed storage. More information