The problem is that the K1 container is built from the latest ubuntu, and 20.04 was just recently released, which became the latest. In the latest image the "RUN apt-get -y install python-igraph" and the "RUN apt install -y python-pip && pip install --upgrade pip" commands break the container building. I think the easiest fix is to fix the image version to "ubuntu:19.10". It worked for me, and with fixing the version similar problems in the future can be avoided.
The problem is that the K1 container is built from the latest ubuntu, and 20.04 was just recently released, which became the latest. In the latest image the "RUN apt-get -y install python-igraph" and the "RUN apt install -y python-pip && pip install --upgrade pip" commands break the container building. I think the easiest fix is to fix the image version to "ubuntu:19.10". It worked for me, and with fixing the version similar problems in the future can be avoided.