[PLATFORM-1554] update deprecated flux api notification.toolkit.fluxcd.io/v1beta1

test/syncers/events/receiver.json

 {
-  "apiVersion": "notification.toolkit.fluxcd.io/v1beta1",
+  "apiVersion": "notification.toolkit.fluxcd.io/v1beta2",
   "kind": "Receiver",
   "metadata": {
     "annotations": {
-      "kubectl.kubernetes.io/last-applied-configuration": "{\"apiVersion\":\"notification.toolkit.fluxcd.io/v1beta1\",\"kind\":\"Receiver\",\"metadata\":{\"annotations\":{},\"name\":\"test\",\"namespace\":\"platform-flux-tenant-config\"},\"spec\":{\"events\":[\"Push Hook\",\"Tag Push Hook\"],\"resources\":[{\"apiVersion\":\"source.toolkit.fluxcd.io/v1beta1\",\"kind\":\"GitRepository\",\"name\":\"test\"}],\"secretRef\":{\"name\":\"flux-webhook-token\"},\"type\":\"gitlab\"}}\n"
+      "kubectl.kubernetes.io/last-applied-configuration": "{\"apiVersion\":\"notification.toolkit.fluxcd.io/v1beta2\",\"kind\":\"Receiver\",\"metadata\":{\"annotations\":{},\"name\":\"test\",\"namespace\":\"platform-flux-tenant-config\"},\"spec\":{\"events\":[\"Push Hook\",\"Tag Push Hook\"],\"resources\":[{\"apiVersion\":\"source.toolkit.fluxcd.io/v1beta1\",\"kind\":\"GitRepository\",\"name\":\"test\"}],\"secretRef\":{\"name\":\"flux-webhook-token\"},\"type\":\"gitlab\"}}\n"
     },
     "creationTimestamp": "2021-06-23T20:04:45Z",
     "generation": 1,
     "name": "test",
     "namespace": "platform-flux-tenant-config",
     "resourceVersion": "325926",
-    "selfLink": "/apis/notification.toolkit.fluxcd.io/v1beta1/namespaces/platform-flux-tenant-config/receivers/test",
+    "selfLink": "/apis/notification.toolkit.fluxcd.io/v1beta2/namespaces/platform-flux-tenant-config/receivers/test",
     "uid": "84a3c717-5363-4470-a80e-cdd657302ac6"
   },
   "spec": {
@@ -42,4 +42,4 @@
     ],
     "url": "/hook/8609574ed008cb75713738bbc61bbf105653de9e2bf50be26e02201e77cc0ad5"
   }
-}
\ No newline at end of file
+}