Fix incorrect unit test description

- description was incorrect: update is not allowed and that's
what the test is verifying

Author: ChunyiLyu

api/v1beta1/schemareplication_webhook_test.go

@@ -97,7 +97,7 @@ var _ = Describe("schema-replication webhook", func() {
 			Expect(updated.ValidateUpdate(&replication)).To(Succeed())
 		})
 
-		It("allows updates on rabbitmqClusterReference.connectionSecret", func() {
+		It("does not allow updates on rabbitmqClusterReference.connectionSecret", func() {
 			connectionScr := SchemaReplication{
 				ObjectMeta: metav1.ObjectMeta{
 					Name: "test-replication",