Replace apps/v1alpha1 with apps/v1beta1 and manually remove generated apps/v1alpha1 files

Manually remove generated apps/v1alpha1 types, protobuf, and api-reference doc files
Manually remove apps/v1alpha1 folder from 1.5 generated client

hack/lib/init.sh

@@ -49,7 +49,7 @@ KUBE_OUTPUT_HOSTBIN="${KUBE_OUTPUT_BINPATH}/$(kube::util::host_platform)"
 # most preferred version for a group should appear first
 KUBE_AVAILABLE_GROUP_VERSIONS="${KUBE_AVAILABLE_GROUP_VERSIONS:-\
 v1 \
-apps/v1alpha1 \
+apps/v1beta1 \
 authentication.k8s.io/v1beta1 \
 authorization.k8s.io/v1beta1 \
 autoscaling/v1 \

hack/make-rules/test-cmd.sh

@@ -1204,7 +1204,7 @@ __EOF__
   kube::test::if_has_string "${output_message}" "/api/v1/namespaces/default/pods 200 OK"
   kube::test::if_has_string "${output_message}" "/api/v1/namespaces/default/replicationcontrollers 200 OK"
   kube::test::if_has_string "${output_message}" "/api/v1/namespaces/default/services 200 OK"
-  kube::test::if_has_string "${output_message}" "/apis/apps/v1alpha1/namespaces/default/statefulsets 200 OK"
+  kube::test::if_has_string "${output_message}" "/apis/apps/v1beta1/namespaces/default/statefulsets 200 OK"
   kube::test::if_has_string "${output_message}" "/apis/autoscaling/v1/namespaces/default/horizontalpodautoscalers 200"
   kube::test::if_has_string "${output_message}" "/apis/batch/v1/namespaces/default/jobs 200 OK"
   kube::test::if_has_string "${output_message}" "/apis/extensions/v1beta1/namespaces/default/deployments 200 OK"

hack/testdata/nginx-petset.yaml

@@ -16,7 +16,7 @@ spec:
   selector:
     app: nginx-petset
 ---
-apiVersion: apps/v1alpha1
+apiVersion: apps/v1beta1
 kind: StatefulSet
 metadata:
   name: nginx