buildx failed with: ERROR: invalid tag "ghcr.io/test-kitchen/dokken/:nightly": invalid reference format

buildx failed with: ERROR: failed to solve: process "/bin/sh -c dnf -y install at binutils bc ca-certificates cronie crontabs diffutils dmidecode e2fsprogs ed ethtool file gettext glibc-langpack-en gnupg2 hostname initscripts iproute iptables iputils lsof nc net-tools nmap make man-db openssl patch passwd procps procps-ng psmisc policycoreutils strace sudo systemd-sysv systemd-udev tcpdump telnet util-linux vim-minimal time wget libxcrypt-compat which && dnf upgrade -y && dnf clean all && rm -rf /var/log/* && find /etc/systemd/system /lib/systemd/system -path '*.wants/*' \\( -name '*getty*' -or -name '*systemd-logind*' -or -name '*systemd-vconsole-setup*' -or -name '*systemd-readahead*' -or -name '*kdump*' -or -name '*dnf-makecache*' -or -name '*udev*' \\) -exec rm -v \\{} \\; && systemctl set-default multi-user.target && systemctl mask dev-hugepages.mount sys-fs-fuse-connections.mount network.service systemd-journal-flush.service" did not complete successfully: exit code: 1