buildx failed with: ERROR: failed to solve: process "/bin/bash -c if [[ \"$UBUNTU_VERSION\" = \"20.04\" ]]; then apt-get install -y ca-certificates && echo 'deb [signed-by=/usr/share/keyrings/kitware-archive-keyring.gpg] https://apt.kitware.com/ubuntu/ focal-rc main' | tee -a /etc/apt/sources.list.d/kitware.list >/dev/null; fi" did not complete successfully: exit code: 100