Fixup vars for cert-manager API version change

I missed this on the first go round. Mea cuppa.

Author: DWSR

config/default/kustomization.yaml

@@ -34,15 +34,15 @@ vars:
   objref:
     kind: Certificate
     group: cert-manager.io
-    version: v1alpha2
+    version: v1
     name: serving-cert # this name should match the one in certificate.yaml
   fieldref:
     fieldpath: metadata.namespace
 - name: CERTIFICATE_NAME
   objref:
     kind: Certificate
     group: cert-manager.io
-    version: v1alpha2
+    version: v1
     name: serving-cert # this name should match the one in certificate.yaml
 - name: SERVICE_NAMESPACE # namespace of the service
   objref: