buildx failed with: ERROR: failed to solve: process "/bin/sh -c export DEBIAN_FRONTEND=noninteractive && apt-get update && apt-key adv --keyserver hkp://keyserver.ubuntu.com:80 --recv-keys 3FA7E0328081BFF6A14DA29AA6A19B38D3D831EF && echo \"deb https://download.mono-project.com/repo/ubuntu stable-${DISTRO_VERSION} main\" | tee /etc/apt/sources.list.d/mono-official-stable.list ; apt-get update && apt-get install --yes mono-devel && apt-get clean --yes && rm -rf /var/lib/apt/lists/*" did not complete successfully: exit code: 100

The run was canceled by @ekilmer.