build: keep the boot partition with label COS_GRUB

    When we repack, we mkfs.vfat for the new boot partition.
    That would break the original partition label, so we need to keep
    the label (means COS_GRUB) as before.

Signed-off-by: Vicente Cheng <vicente.cheng@suse.com>

scripts/package-harvester-os

@@ -96,7 +96,7 @@ cp "${extract_dir}/rootfs.squashfs" "${ARTIFACTS_DIR}/${PROJECT_PREFIX}-rootfs-$
 # and copy EFI files to it to make it UEFI bootable
 uefi_img="${extract_dir}/boot/uefi.img"
 dd if=/dev/zero of="${uefi_img}" bs=1k count=4096 status=progress
-mkfs.vfat "${uefi_img}"
+mkfs.vfat "${uefi_img}" -n COS_GRUB
 mcopy -s -i "${uefi_img}" "${extract_dir}/EFI" ::
 
 # Remove original ISO, and repack it using xorriso