fix azure setup in administrator docs (zalando#2059)

in the OperatorConfiguration CRD  "pod_environment_secret" and "pod_environment_configmap" properties is located under "kubernetes" object. aws_or_gcp object does not have these properties.

Author: dogaakcinar

docs/administrator.md

@@ -1099,9 +1099,10 @@ and `pod-env-overrides` resources applied to your cluster, ensure that the opera
 is set up like the following:
 ```yml
 ...
-aws_or_gcp:
+kubernetes:
   pod_environment_secret: "psql-backup-creds"
   pod_environment_configmap: "postgres-operator-system/pod-env-overrides"
+aws_or_gcp:
   wal_az_storage_account: "postgresbackupsbucket28302F2"  # name of storage account to save the WAL-G logs
 ...
 ```