Add EventPolicy to storage version migrator (#8384)

While this is not strictly needed, this prevents issues we could run
into eventually with storage version migrations.

Signed-off-by: Pierangelo Di Pilato <pierdipi@redhat.com>

config/post-install/storage-version-migrator.yaml

@@ -55,6 +55,7 @@ spec:
             - "subscriptions.messaging.knative.dev"
             - "triggers.eventing.knative.dev"
             - "jobsinks.sinks.knative.dev"
+            - "eventpolicies.eventing.knative.dev"
           securityContext:
             allowPrivilegeEscalation: false
             readOnlyRootFilesystem: true