Automatic merge from submit-queue (batch tested with PRs 49705, 53229). 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>.
Fix kubeadm upgrade grammar.
**What this PR does / why we need it**:
I noticed an erroneous word in the output from the kubeadm upgrade docs. This error message currently reads:
"Note: Before you **do** can perform this upgrade, you have to update kubeadm to..."
**Release note**:
```release-note
NONE
```
CC @kubernetes/sig-cluster-lifecycle-pr-reviews
628df56b2c