Adding Azure.Identity release notes to 2020-08/dotnet.md (#1687)

* Adding Azure.Identity release notes to 2020-08/dotnet.md

* fixing heading size under Azure.Identity

releases/2020-08/dotnet.md

@@ -10,6 +10,7 @@ The Azure SDK team is pleased to announce our August 2020 client library release
 
 #### GA
 
+- Identity
 - Key Vault (Certificates, Keys, Secrets)
 - Search
 - Text Analytics
@@ -38,6 +39,8 @@ To install any of our packages, please search for them via `Manage NuGet Package
  $> dotnet add package Azure.Extensions.AspNetCore.DataProtection.Blobs
  $> dotnet add package Azure.Extensions.AspNetCore.DataProtection.Keys
 
+ $> dotnet add package Azure.Identity
+
  $> dotnet add package Azure.Messaging.EventHubs --version 5.2.0-preview.2
  $> dotnet add package Azure.Messaging.EventHubs.Processor --version 5.2.0-preview.2
 
@@ -113,6 +116,22 @@ If you have a bug or feature request for one of the libraries, please [file an i
 
 - Made the `TrainingFileFilter` constructor public.
 
+### Azure Identity [Changelog](https://github.com/Azure/azure-sdk-for-net/blob/master/sdk/identity/Azure.Identity/CHANGELOG.md#120-2020-08-10)
+
+#### New Features
+- Includes changes from 1.2.0-preview.1 to 1.2.0-preview.6
+  - Added credential types for authentication in the development environment `VisualStudioCredential`, `VisualStudioCodeCredential`, `AzureCliCredential`
+  - Updated `DefaultAzureCredential` authentication flow to contain new development credential types
+  - Added `AzureAuthorityHosts` to simplify authentication in sovereign clouds
+
+#### Breaking Changes
+- Removing Application Authentication APIs for GA release. These will be reintroduced in 1.3.0-preview.
+
+#### Fixes and improvements
+- Fixed excess errors in `DefaultAzureCredential` tracing (Issue [#10659](https://github.com/Azure/azure-sdk-for-net/issues/10659))
+- Fixed concurrency issue in `DefaultAzureCredential` (Issue [#13044](https://github.com/Azure/azure-sdk-for-net/issues/13044))
+
+
 ### Azure Key Vault
 
 #### Certificates 4.1.0 [Changelog](https://github.com/Azure/azure-sdk-for-net/blob/Azure.Security.KeyVault.Certificates_4.1.0/sdk/keyvault/Azure.Security.KeyVault.Certificates/CHANGELOG.md#410-2020-08-11)