Update README.md with MSTest.Sdk information (#5214)

Author: stan-sz

README.md

@@ -36,6 +36,7 @@ MSTest is shipped as NuGet packages that can be added to your projects. The foll
 | MSTest.TestFramework | This package includes the libraries for writing tests with MSTest. To ensure the discovery and execution of your tests, install the `MSTest.TestAdapter` package. | [![#](https://img.shields.io/nuget/v/mstest.testframework.svg?style=flat)](http://www.nuget.org/packages/MSTest.TestFramework/) | [![#](https://img.shields.io/nuget/vpre/mstest.testframework.svg?style=flat)](http://www.nuget.org/packages/MSTest.TestFramework/) | [Azure Artifacts](https://dnceng.visualstudio.com/public/_artifacts/feed/test-tools/NuGet/MSTest.TestFramework/versions) |
 | MSTest.TestAdapter | This package includes the adapter logic to discover and run tests. For access to the testing framework, install the `MSTest.TestFramework` package. | [![#](https://img.shields.io/nuget/v/mstest.testadapter.svg?style=flat)](http://www.nuget.org/packages/MSTest.TestAdapter/) | [![#](https://img.shields.io/nuget/vpre/mstest.testadapter.svg?style=flat)](http://www.nuget.org/packages/MSTest.TestAdapter/) | [Azure Artifacts](https://dnceng.visualstudio.com/public/_artifacts/feed/test-tools/NuGet/MSTest.TestAdapter/versions) |
 | MSTest.Analyzers | This package includes code analyzers and code fixes for MSTest. | [![#](https://img.shields.io/nuget/v/mstest.analyzers.svg?style=flat)](http://www.nuget.org/packages/MSTest.Analyzers/) | [![#](https://img.shields.io/nuget/vpre/mstest.analyzers.svg?style=flat)](http://www.nuget.org/packages/MSTest.Analyzers/) | [Azure Artifacts](https://dnceng.visualstudio.com/public/_artifacts/feed/test-tools/NuGet/MSTest.Analyzers/versions) |
+| MSTest.Sdk | This is a [MSBuild Project SDK](https://learn.microsoft.com/visualstudio/msbuild/how-to-use-project-sdk) package that greatly simplifies a test project structure. See [MSTest SDK Overview](https://aka.ms/mstest/sdk) for details. | [![#](https://img.shields.io/nuget/v/mstest.svg?style=flat)](http://www.nuget.org/packages/MSTest.Sdk/) | [![#](https://img.shields.io/nuget/vpre/mstest.svg?style=flat)](http://www.nuget.org/packages/MSTest.Sdk/) | [Azure Artifacts](https://dnceng.visualstudio.com/public/_artifacts/feed/test-tools/NuGet/MSTest.Sdk/versions) |
 
 ## License