{AzureSubscription} fixes Azure#20812 fix the workload parameter (Azure#20842)

* {AzureSubscription} fixes Azure#20812 fix the workload parameter

fixes Azure#20812 

While we run the PS cmdlet `New-AzSubscriptionAlias` it fails with the error:

New-AzSubscriptionAlias -AliasName MyTestAlias -BillingScope '/providers/Microsoft.Billing/billingAccounts/XXXXXX/enrollmentAccounts/XXXXXX' -SubscriptionName MysSubscription

New-AzSubscriptionAlias: Operation returned an invalid status code 'BadRequest'

Debug output:
{
  "error": {
    "code": "InvalidWorkLoad",
    "message": "Invalid WorkLoad provided, Only Production or DevTest are allowed"
  },
  "code": "InvalidWorkLoad",
  "message": "Invalid WorkLoad provided, Only Production or DevTest are allowed"
}

This PR makes the workload parameter mandatory to avoid the above error.

* Update ChangeLog.md

* Update src/Subscription/Subscription/ChangeLog.md

Co-authored-by: Beisi Zhou <zhoubeisi@gmail.com>

* Updating the help docs for New-AzSubscriptionAlias

* Update src/Subscription/Subscription/ChangeLog.md

---------

Co-authored-by: Beisi Zhou <zhoubeisi@gmail.com>

Author: navba-MSFT

src/Subscription/Subscription/ChangeLog.md

@@ -18,6 +18,7 @@
         - Additional information about change #1
 -->
 ## Upcoming Release
+* Fixed `New-AzSubscriptionAlias` cmdlet to make the Workload parameter mandatory.
 
 ## Version 0.8.1
 * Updated Microsoft.Azure.Management.Subscription .Net SDK version to 2.0.0

src/Subscription/Subscription/Cmdlets/NewAzureRmSubscriptionAlias.cs

@@ -50,7 +50,7 @@ public ISubscriptionClient SubscriptionClient
         [Parameter(Mandatory = false, HelpMessage = "Billing Scope")]
         public string BillingScope { get; set; }
 
-        [Parameter(Mandatory = false, HelpMessage = "Type of Workload")]
+        [Parameter(Mandatory = true, HelpMessage = "Type of Workload")]
         [PSArgumentCompleter("Production", "DevTest")]
         public string Workload { get; set; }
 

src/Subscription/Subscription/help/New-AzSubscriptionAlias.md

@@ -146,14 +146,14 @@ Accept wildcard characters: False
 ```
 
 ### -Workload
-Type of Workload
+Type of Workload. Accepted values: DevTest, Production.
 
 ```yaml
 Type: System.String
 Parameter Sets: (All)
 Aliases:
 
-Required: False
+Required: True
 Position: Named
 Default value: None
 Accept pipeline input: False