packet_centos8-docker.yml

* Defaults: replace docker with containerd as our default container_manager

* CI: Use docker for download_localhost test

* Defaults: with container_manager=containerd we need etcd_deployment_type=host

* CI: Run weave jobs with docker

* CI: Vagrant don't download_force_cache

* CI: Fix upgrade tests

* should run compatible with old settings, this means docker
* we need to run with a distro that has at least modern containerd,
  this means move from debian9 to debian10 to allow `containerd_version`
  to match between 2.17 and master