[stable/stolon] upgrade api version for kubernetes 1.16+ (#19289)

The v1.16 release will stop serving the following deprecated API versions in favor of newer and more stable API versions:

* DaemonSet, Deployment, StatefulSet, and ReplicaSet (in the extensions/v1beta1 and apps/v1beta2 API groups)
  * Migrate to use the apps/v1 API, available since v1.9. Existing persisted data can be retrieved/updated via the apps/v1 API.

See https://kubernetes.io/blog/2019/07/18/api-deprecations-in-1-16/

Signed-off-by: Yujun Zhang <yujunz@nvidia.com>

stable/stolon/Chart.yaml

@@ -1,6 +1,6 @@
 apiVersion: v1
 name: stolon
-version: 1.5.0
+version: 1.5.1
 appVersion: 0.13.0
 description: Stolon - PostgreSQL cloud native High Availability.
 home: https://github.com/sorintlab/stolon

stable/stolon/templates/keeper-statefulset.yaml

@@ -1,4 +1,4 @@
-apiVersion: apps/v1beta2
+apiVersion: apps/v1
 kind: StatefulSet
 metadata:
   name: {{ template "stolon.fullname" . }}-keeper

stable/stolon/templates/proxy-deployment.yaml

@@ -1,4 +1,4 @@
-apiVersion: apps/v1beta2
+apiVersion: apps/v1
 kind: Deployment
 metadata:
   name: {{ template "stolon.fullname" . }}-proxy

stable/stolon/templates/sentinel-deployment.yaml

@@ -1,4 +1,4 @@
-apiVersion: apps/v1beta2
+apiVersion: apps/v1
 kind: Deployment
 metadata:
   name: {{ template "stolon.fullname" . }}-sentinel