Upgrade to podman breaks --docker feature

[istathar]

There may be a problem with how podman interprets the --user argument to docker run. The tempdir being mapped in (as in /tmp/publish-kBywA9 or whatever) isn't readable by the child docker process, resulting in latexmk failing.

[istathar]

[this is as encountered on upgrading a user's workstation from Fedora 30 to Fedora 31; since they upgraded to CGroups 2 the docker binary from Docker, Inc is no longer supported. podman is intended to be a command-line compatible drop-in replacement but as it runs as user (not as root) there appear to be some permission issues]