* Update Kubernetes to v1.21.0
* Update to golang v1.16.2
* Update dependent modules to track with upstream
* Switch to upstream flannel
* Track changes to upstream cloud-controller-manager and FeatureGates
Signed-off-by: Brad Davidson <brad.davidson@rancher.com>
Remove $NOTIFY_SOCKET, if present, from env when invoking containerd to
prevent gratuitous notifications sent to systemd.
Signed-off-by: Jacob Blain Christen <jacob@rancher.com>