docs(azure): correct Azure Stack example version and note expiry limit (#6522)

Signed-off-by: Alexander Chernov <alexander@chernov.it>

docs/provider/azure-key-vault.md

@@ -165,7 +165,7 @@ spec:
 For Azure Stack Hub or Azure Stack Edge environments:
 
 ```yaml
-apiVersion: external-secrets.io/v1beta1
+apiVersion: external-secrets.io/v1
 kind: SecretStore
 metadata:
   name: azure-stack-backend
@@ -264,6 +264,9 @@ You can optionally attach metadata to the secret via the `spec.data[].metadata`
 !!! note
     Omitting `contentType` (or setting it to an empty string) is interpreted as "don't change" rather than "clear": if the secret in Azure Key Vault already has a `ContentType` set, it will be preserved on update. There is currently no way to clear an existing `ContentType` via PushSecret — if you need to remove it, delete the secret from Azure Key Vault directly and let PushSecret recreate it.
 
+!!! note
+    `expirationDate` is applied only when the SecretStore uses the legacy SDK (the default). When `useAzureSDK: true` is set (required for `customCloudConfig`, including Azure Stack and Azure China Workload Identity), `expirationDate` is currently ignored: the secret is pushed without an expiry, and changing `expirationDate` alone does not trigger an update. If you need an expiry in those environments, set it directly on the secret in Azure Key Vault.
+
 #### Pushing to a Key
 The first step is to generate a valid private key. Supported formats include `PRIVATE KEY`, `RSA PRIVATE KEY` AND `EC PRIVATE KEY` (EC/PKCS1/PKCS8 types). After uploading your key to a Kubernetes Secret, the next step is to create a PushSecret manifest with the following configuration: