travis: Tie to a specific minikube version
travis: Tie to a specific minikube version

Signed-off-by: Fabian Deutsch <de69c509e52dfe544d526a81279fe21e1252748c@fedoraproject.org>

kubevirt/containerized-data-importer,kubevirt/containerized-data-importer,kubevirt/containerized-data-importer