expamples: Fixed examples/k8s/psp.yaml file

PodSecurityPolicy (in the extensions/v1beta1 API group)
Migrated to use the policy/v1beta1 API, available since v1.10. Existing persisted data can be retrieved/updated via the policy/v1beta1 API.

Signed-off-by: knrt10 <tripathi.kautilya@gmail.com>

examples/k8s/psp.yaml

@@ -1,4 +1,4 @@
-apiVersion: extensions/v1beta1
+apiVersion: policy/v1beta1
 kind: PodSecurityPolicy
 metadata:
   name: weave-scope
@@ -18,4 +18,4 @@ spec:
     rule: RunAsAny
   volumes:
   - secret
-  - hostPath
+  - hostPath