Add support for podman
Because Fedora Linux 31 removed cgroups-v2 and docker cannot work now. Podman is CLI-compatible with Docker, so it boils down to switch to the variable instead of calling docker directly.
Because Fedora Linux 31 removed cgroups-v2 and docker cannot work now. Podman is CLI-compatible with Docker, so it boils down to switch to the variable instead of calling docker directly.