`Package Docker` CI job failed during release

[adpaco-aws]

The Package Docker CI job failed during the release of kani-0.40.0. Here's the run: https://github.com/model-checking/kani/actions/runs/6724859832/job/18278536436

And the error:

/usr/bin/docker buildx build --file scripts/ci/Dockerfile.bundle-release-20-04 --iidfile /tmp/docker-build-push-YjJTto/iidfile --label org.opencontainers.image.source=git://github.com/model-checking/kani.git --label org.opencontainers.image.version= --label org.opencontainers.image.licenses=Apache-2.0 OR MIT --tag ghcr.io/model-checking/kani-ubuntu-20.04: --tag ghcr.io/model-checking/kani-ubuntu-20.04:latest --metadata-file /tmp/docker-build-push-YjJTto/metadata-file --push .
ERROR: invalid tag "ghcr.io/model-checking/kani-ubuntu-20.04:": invalid reference format
Error: buildx failed with: ERROR: invalid tag "ghcr.io/model-checking/kani-ubuntu-20.04:": invalid reference format