the kubernetes/kubeadm default branch got renamed to "main"

[Lubomir I. Ivanov]

hello,

after a number of PRs, we flipped the switch and renamed the default
branch of the kubernetes/kubeadm repository to be "main" instead of
"master".

tracking issue:
https://github.com/kubernetes/kubeadm/issues/2589

https://cs.k8s.io/ does not reveal any additional repositories with
up-to-date docs / scripts that use the repository "master" branch, but
in case if you find any just drop us a notice in #kubeadm on k8s slack
or PR the changes directly. there is currently one pending PR to be
merged in k/community.

to update your local clone you can use this:

$ git branch -m master main
$ git fetch origin
$ git branch -u origin/main main
$ git remote set-head origin -a

thank you
--
lubomir