Added breaking changes for Invoke-AzKeyVaultKeyOperation (#21527)

Author: BethanyZhou

src/KeyVault/KeyVault/ChangeLog.md

@@ -18,6 +18,9 @@
         - Additional information about change #1
 -->
 ## Upcoming Release
+* Added breaking changes for `Invoke-AzKeyVaultKeyOperation`. The encoded/decoded way between string and bytes in `Invoke-AzKeyVaultKeyOperation` will change to UTF8. 
+    - This change will take effect on 5/23/2023
+    - The change is expected to take effect from the version 5.0.0
 * Updated Azure.Core to 1.31.0.
 
 ## Version 4.9.2

src/KeyVault/KeyVault/Commands/Key/InvokeAzureKeyVaultOperation.cs

@@ -1,5 +1,6 @@
 using Microsoft.Azure.Commands.KeyVault.Models;
 using Microsoft.Azure.Commands.ResourceManager.Common.ArgumentCompleters;
+using Microsoft.WindowsAzure.Commands.Common.CustomAttributes;
 
 using System;
 using System.Management.Automation;
@@ -14,6 +15,7 @@ namespace Microsoft.Azure.Commands.KeyVault.Commands.Key
     /// 3. Wraps a symmetric key using a specified key.
     /// 4. Unwraps a symmetric key using the specified key that was initially used for wrapping that key.
     /// </summary>
+    [GenericBreakingChange("The encoded/decoded way between string and bytes will change to UTF8.", "5.0.0", "05/23/2023")]
     [Cmdlet(VerbsLifecycle.Invoke, ResourceManager.Common.AzureRMConstants.AzurePrefix + "KeyVaultKeyOperation", SupportsShouldProcess = true, DefaultParameterSetName = ByVaultNameParameterSet)]
     [OutputType(typeof(PSKeyOperationResult))]
     public class InvokeAzureKeyVaultKeyOperation : KeyVaultKeyCmdletBase