Merge pull request #35731 from janetkuo/statefulset-v1beta1

Automatic merge from submit-queue

Move Statefulset (previously PetSet) to v1beta1

**What this PR does / why we need it**: #28718

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

**Special notes for your reviewer**: depends on #35663 (PetSet rename)
cc @erictune @foxish @kubernetes/sig-apps 

**Release note**:

``` release-note
v1beta1/StatefulSet replaces v1alpha1/PetSet.
```

examples/cockroachdb/cockroachdb-petset.yaml

@@ -54,7 +54,7 @@ spec:
   selector:
     app: cockroachdb
 ---
-apiVersion: apps/v1alpha1
+apiVersion: apps/v1beta1
 kind: PetSet
 metadata:
   name: cockroachdb

examples/storage/cassandra/README.md

@@ -179,7 +179,7 @@ of three pods.
 <!-- BEGIN MUNGE: EXAMPLE cassandra-petset.yaml -->
 
 ```yaml
-apiVersion: "apps/v1alpha1"
+apiVersion: "apps/v1beta1"
 kind: StatefulSet
 metadata:
   name: cassandra

examples/storage/cassandra/cassandra-petset.yaml

@@ -1,4 +1,4 @@
-apiVersion: "apps/v1alpha1"
+apiVersion: "apps/v1beta1"
 kind: StatefulSet
 metadata:
   name: cassandra