Mender-convert failure using raspberrypi4_ubuntu_config

Downloaded mender-convert as part of the tutorial on your docs site. When running:

MENDER_ARTIFACT_NAME=release-1 ./docker-mender-convert \ 
--disk-image input/golden-image-1.img \
--config configs/raspberrypi4_ubuntu_config \
--overlay rootfs_overlay_demo/

A fatal error halts the script almost immediately, with the reported error:

configs/raspberrypi_config: line 13: RASPBERRYPI_CONFIG: unbound variable

Now, if mender-convert is run calling raspberrypi4_config instead, a different error occurs at the end of the build. I'll file a report on that one as well.

Dell Green and I had a conversation on the Mender Hub and he suggested editing the ubuntu config to remove the raspberrypi_binaries entry and add RASPBERRYPI_CONFIG="raspberrypi4". This resolved the issue, and I was able to continue the conversion (until it was determined that I needed to change disk size, but that's obviously outside the scope of this report).

Pull request being created on github now.