Deprecated configuration key iso_checksum_type

[maudmcok]

1 error occurred:
* Deprecated configuration key: 'iso_checksum_type'. Please call `packer fix

Correction

clong/DetectionLab#469 (comment)

[CrabbiusDankus]

Deleting the 'iso_checksum_type' and 'headless: false' lines fixed it for me.

Thanks maudmcok