Merge pull request #46220 from superbrothers/add-statefulset

Automatic merge from submit-queue (batch tested with PRs 47776, 46220, 46878, 47942, 47947)

Add statefulset to the completion candidates of kubectl scale

**What this PR does / why we need it**: This commit adds `statefulset` to the completion candidates of kubectl scale.
```
$ kubectl scale <tab>
deployment             job                    --replicas             replicaset             replicationcontroller  statefulset
```

**Which issue this PR fixes** *(optional, in `fixes #<issue number>(, fixes #<issue_number>, ...)` format, will close that issue when PR gets merged)*: fixes kubernetes/kubectl#14

**Special notes for your reviewer**:

**Release note**:

```release-note
NONE
```

pkg/kubectl/cmd/scale.go

@@ -60,7 +60,7 @@ var (
 func NewCmdScale(f cmdutil.Factory, out io.Writer) *cobra.Command {
 	options := &resource.FilenameOptions{}
 
-	validArgs := []string{"deployment", "replicaset", "replicationcontroller", "job"}
+	validArgs := []string{"deployment", "replicaset", "replicationcontroller", "job", "statefulset"}
 	argAliases := kubectl.ResourceAliases(validArgs)
 
 	cmd := &cobra.Command{