Automatic merge from submit-queue (batch tested with PRs 46946, 45792). If you want to cherry-pick this change to another branch, please follow the instructions <a href="https://github.com/kubernetes/community/blob/master/contributors/devel/cherry-picks.md">here</a>.

kubectl config get-contexts: sort output

This sorts the output of kubectl config get-contexts because the ordering is otherwise non-stable and makes it harder to find the context you're looking for when you have more than a few.

```release-note
The output of kubectl config get-contexts is now sorted alphabetically by the context name.
```