Update KMS API to v2 (kubernetes#2561)

KMS v1 API is deprecated and in v1.29 core K8s won't allow it with
default feature gates set. This commit makes sure we're proposing
configuration of v2 API in example EncryptionConfigs.

Author: dulek

docs/barbican-kms-plugin/using-barbican-kms-plugin.md

@@ -84,7 +84,7 @@ plane nodes.
 kubectl apply -f https://raw.githubusercontent.com/kubernetes/cloud-provider-openstack/master/manifests/barbican-kms/ds.yaml
 ```
 *recommendation:* Use the tag corresponding to your Kubernetes release, for
-example `release-1.25` for kubernetes version 1.25.
+example `release-1.29` for kubernetes version 1.29.
 
 
 ### Create encryption configuration
@@ -99,9 +99,9 @@ resources:
     - secrets
     providers:
     - kms:
-        name : barbican
+        apiVersion: v2
+        name: barbican
         endpoint: unix:///var/lib/kms/kms.sock
-        cachesize: 100
     - identity: {}
 ```
 

manifests/barbican-kms/encryption-config.yaml

@@ -5,7 +5,7 @@ resources:
     - secrets
     providers:
     - kms:
+        apiVersion: v2
         name: barbican
         endpoint: unix:///var/lib/kms/kms.sock
-        cachesize: 20
     - identity: {}