Bump HorizontalPodAutoscaler apiVersion to v2

Before this, we get a warning when applying the HPA:

    Warning: autoscaling/v2beta1 HorizontalPodAutoscaler is deprecated in v1.22+, unavailable in v1.25+; use autoscaling/v2 HorizontalPodAutoscaler

This also bumps the min version to 1.23.

Signed-off-by: Vincent Demeester <vdemeest@redhat.com>

config/webhook-hpa.yaml

@@ -12,7 +12,7 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-apiVersion: autoscaling/v2beta1
+apiVersion: autoscaling/v2
 kind: HorizontalPodAutoscaler
 metadata:
   name: tekton-pipelines-webhook
@@ -38,4 +38,6 @@ spec:
     - type: Resource
       resource:
         name: cpu
-        targetAverageUtilization: 100
+        target:
+          type: Utilization
+          averageUtilization: 100

docs/enabling-ha.md

@@ -86,7 +86,7 @@ kubectl -n tekton-pipelines scale deployment tekton-pipelines-webhook --replicas
 You can also modify the [HorizontalPodAutoscaler](./../config/webhook-hpa.yaml) to set a minimum number of replicas:
 
 ```yaml
-apiVersion: autoscaling/v2beta1
+apiVersion: autoscaling/v2
 kind: HorizontalPodAutoscaler
 metadata:
   name: tekton-pipelines-webhook