Creating a BZ to get https://github.com/openshift/installer/pull/1764 into 4.1 release. If an install config is created without an APIVersion the error meessage is: " unexpected error cannot upconvert from version ". This is a confusing error message.
Verified it with version: 4.1.0-0.nightly-2019-06-26-214813 # openshift-install create cluster FATAL failed to fetch Terraform Variables: failed to load asset "Install Config": failed to upconvert install config: cannot upconvert from version v3
Since the problem described in this bug report should be resolved in a recent advisory, it has been closed with a resolution of ERRATA. For information on the advisory, and where to find the updated files, follow the link below. If the solution does not work for you, open a new bug report. https://access.redhat.com/errata/RHBA-2019:1635