support account cold tier (#25820)

Author: yifanz7

src/Storage/Storage.Management/ChangeLog.md

@@ -18,6 +18,9 @@
         - Additional information about change #1
 -->
 ## Upcoming Release
+* Supported account tier Cold
+    - `New-AzStorageAccount`
+    - `Set-AzStorageAccount`
 * Updated list share output display format 
     - `Get-AzStorageShare`
 

src/Storage/Storage.Management/StorageAccount/NewAzureStorageAccount.cs

@@ -116,6 +116,7 @@ public string Kind
             HelpMessage = "Storage Account Access Tier.")]
         [ValidateSet(AccountAccessTier.Hot,
             AccountAccessTier.Cool,
+            AccountAccessTier.Cold,
             IgnoreCase = true)]
         public string AccessTier { get; set; }
 

src/Storage/Storage.Management/StorageAccount/SetAzureStorageAccount.cs

@@ -99,6 +99,7 @@ public SwitchParameter Force
             HelpMessage = "Storage Account Access Tier.")]
         [ValidateSet(AccountAccessTier.Hot,
             AccountAccessTier.Cool,
+            AccountAccessTier.Cold,
             IgnoreCase = true)]
         public string AccessTier { get; set; }
 

src/Storage/Storage.Management/StorageAccount/StorageAccountBaseCmdlet.cs

@@ -57,6 +57,7 @@ protected struct AccountAccessTier
         {
             internal const string Hot = "Hot";
             internal const string Cool = "Cool";
+            internal const string Cold = "Cold";
         }
         protected struct AzureBlobType
         {