update change log for KeyVault track 2 mgmt sdk

sdk/keyvault/Azure.Management.KeyVault/CHANGELOG.md

@@ -2,5 +2,87 @@
 
 ## 1.0.0-preview.1
 
-### New Features
-- Initial preview of Azure Management KeyVault SDK based on Azure.Core
+This package follows the new Azure SDK guidelines which provide a number of core capabilities that are shared amongst all Azure SDKs, including the intuitive Azure Identity library, an HTTP Pipeline with custom policies, error-handling, distributed tracing, and much more.
+
+This is a Public Preview version, so expect incompatible changes in subsequent releases as we improve the product. To provide feedback, please submit an issue in our [Azure SDK for .NET GitHub repo](https://github.com/Azure/azure-sdk-for-net/issues).
+
+### General New Features
+
+    - Support MSAL.NET, Azure.Identity is out of box for supporting MSAL.NET
+    - Support [OpenTelemetry](https://opentelemetry.io/) for distributed tracing
+    - HTTP pipeline with custom policies
+    - Better Error-handling
+    - Support uniform telemetry across all languages
+
+> NOTE: For more information about unified authentication, please refer to [Azure Identity documentation for .NET](https://docs.microsoft.com//dotnet/api/overview/azure/identity-readme?view=azure-dotnet)
+
+### Migration from Previous Version of Azure Management SDK
+
+#### Package Name
+The package name has been changed from `Microsoft.Azure.Management.KeyVault` to `Azure.Management.KeyVault`
+
+#### Management Client Changes
+
+Example: Create a Key Vault Instace:
+
+Before upgrade:
+```csharp
+using Microsoft.Azure.Management.KeyVault;
+using Microsoft.Azure.Management.KeyVault.Models;
+using Microsoft.Rest;
+
+var tokenCredentials = new TokenCredentials("YOUR ACCESS TOKEN");
+var keyVaultManagementClient = new KeyVaultManagementClient(tokenCredentials);
+var vault = await keyVaultManagementClient.Vaults.BeginCreateOrUpdateAsync
+                (
+                    resourceGroupName,
+                    vaultName,
+                    parameters
+                );
+```
+
+After upgrade:
+```csharp
+using Azure.Identity;
+using Azure.Management.KeyVault;
+using Azure.Management.KeyVault.Models;
+
+var keyVaultManagementClient = new KeyVaultManagementClient(SubscriptionId,
+            new DefaultAzureCredential(),
+            new KeyVaultManagementClientOptions());
+var vaultsClient = keyVaultManagementClient.GetVaultsClient();
+
+var vault = await vaultsClient.StartCreateOrUpdateAsync(
+            resourceGroupName,
+            vaultName,
+            parameters
+            );
+var vaultValue = (await vault.WaitForCompletionAsync()).Value;
+
+```
+
+#### Object Model Changes
+
+Example: Create a Permissions Model
+
+Before upgrade:
+```csharp
+var permissions = new Permissions
+                {
+                    Keys = new string[] { "all" },
+                    Secrets = new string[] { "all" },
+                    Certificates = new string[] { "all" },
+                    Storage = new string[] { "all" },
+                }
+```
+
+After upgrade:
+```csharp
+var permissions = new Permissions
+            {
+                Keys = new KeyPermissions[] { new KeyPermissions("all") },
+                Secrets = new SecretPermissions[] { new SecretPermissions("all") },
+                Certificates = new CertificatePermissions[] { new CertificatePermissions("all") },
+                Storage = new StoragePermissions[] { new StoragePermissions("all") },
+            };
+```