Automatic merge from submit-queue (batch tested with PRs 49870, 49416, 49872, 49892, 49908)
Make "kubeadm version" json format output more readable.
**What this PR does / why we need it**:
Add indent to json format output.
**Which issue this PR fixes** *(optional, in `fixes #<issue number>(, fixes #<issue_number>, ...)` format, will close that issue when PR gets merged)*: fixes #
ref: #43750#46598
**Special notes for your reviewer**:
output example:
```
#kubeadm version -o json
{
"clientVersion": {
"major": "1",
"minor": "8+",
"gitVersion": "v1.8.0-alpha.2.1026+d8205661b700c6-dirty",
"gitCommit": "d8205661b700c6f99c33ea0ac1e5ed3e49c202b2",
"gitTreeState": "dirty",
"buildDate": "2017-07-31T12:14:28Z",
"goVersion": "go1.8.3",
"compiler": "gc",
"platform": "linux/amd64"
}
}
```
**Release note**:
```release-note
NONE
```
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