Update readme and version history for v6.0 (#188)

* Update README.md

* Update VERSION_HISTORY.md

* Update VERSION_HISTORY.md

README.md

@@ -22,7 +22,7 @@ Lottie-Windows consists of 3 related products:
 ## Build Status
 | Target | Branch | Status | Recommended NuGet package |
 | ------ | ------ | ------ | ------ |
-| 5.1.1 release | master | [![Build Status](https://dev.azure.com/dotnet/WindowsCommunityToolkit/_apis/build/status/Microsoft.Toolkit.Uwp.UI.Lottie?branchName=master)](https://dev.azure.com/dotnet/WindowsCommunityToolkit/_build/latest?definitionId=61&branchName=master) | [![NuGet](https://img.shields.io/nuget/v/Microsoft.Toolkit.Uwp.UI.Lottie.svg)](https://www.nuget.org/packages/Microsoft.Toolkit.Uwp.UI.Lottie/) |
+| 6.0.0 release | master | [![Build Status](https://dev.azure.com/dotnet/WindowsCommunityToolkit/_apis/build/status/Microsoft.Toolkit.Uwp.UI.Lottie?branchName=master)](https://dev.azure.com/dotnet/WindowsCommunityToolkit/_build/latest?definitionId=61&branchName=master) | [![NuGet](https://img.shields.io/nuget/v/Microsoft.Toolkit.Uwp.UI.Lottie.svg)](https://www.nuget.org/packages/Microsoft.Toolkit.Uwp.UI.Lottie/) |
 
 ## Feedback and Requests
 Please use [GitHub Issues](https://github.com/windows-toolkit/Lottie-Windows/issues) for bug reports and feature requests.

VERSION_HISTORY.md

@@ -2,13 +2,34 @@
 
 Lottie-Windows aligns its major version with the Windows Community Toolkit.
 
+## 6.0.0
+
+Support for ARM64.
+
+The following Adobe After Effects are also supported:
+
+**Layer types**
+* Image (codegen only)
+
+**Fill**
+* Linear and Radial Gradient
+
+**Mask**
+* Subtract
+
+**Track mattes**
+* Alpha matte
+
+Lottie-Windows is version-adaptive when animation features require different UAP versions.
+
+
 ## 5.1.1
 
 Support for Bodymovin v5.5.0 with changes to the JSON schema.
 
 ## 5.1.0 — Initial Release
 
-The following Adobe AfterEffects features are supported:
+The following Adobe After Effects features are supported:
 
 **Layer types**
 * Precomp