`kubeadm config upload` is a GA command that has been deprecated and scheduled
for removal since Kubernetes 1.15 (released 06/19/2019). This change will
finally removed it in Kubernetes 1.19 (planned for August 2020).
The original command has long since been replaced by a GA init phase:
`kubeadm init phase upload-config`
Signed-off-by: Rostislav M. Georgiev <rostislavg@vmware.com>