docker-compose does not work with cgroupsv2

[calebbrown]

While researching #378 I discovered that the docker-compose setup in example/e2e does not appear to work under cgroupsv2.

docker run --cgroupns=host does work, but there is no equivalent for use in docker-compose.yml.

This is an issue with support in upstream docker-compose. See: compose-spec/compose-spec#148, docker/compose#8167

[calebbrown]

A work around is to create/edit /etc/docker/daemon.json with the following:

{
    "default-cgroupns-mode": "host"
}

[calebbrown]

Added docs in #404