DFU update module generator script bug

@Utsav_Shah the Update Module has to be installed on the device. This is explained in the tutorial here: Device Firmware Update (DFU).

An Update Module is the client side handling for such artifacts. The upstream source is:

More details on Update Modules:
https://docs.mender.io/artifact-creation/create-a-custom-update-module

Greetz,
Josef