Update README to include URL to preview version

Author: josesimoes

Diff for: README.md

@@ -10,11 +10,11 @@ This repo contains .NET **nanoFramework** Visual Studio extension and associated
 
 ## Build status
 
-| Component | Build Status | Stable version |
+| Component | Build Status | Stable version | Preview version |
 |:-|---|---|
-| Visual Studio 2022 extension | [![Build Status](https://dev.azure.com/nanoframework/Visual-Studio-extension/_apis/build/status/nanoframework.nf-Visual-Studio-extension)](https://dev.azure.com/nanoframework/Visual-Studio-extension/_build/latest?definitionId=17) | [![Visual Studio Marketplace](https://img.shields.io/vscode-marketplace/d/nanoframework.nanoFramework-VS2022-Extension.svg)](https://marketplace.visualstudio.com/items?itemName=nanoframework.nanoFramework-VS2022-Extension) |
-| Visual Studio 2019 extension | [![Build Status](https://dev.azure.com/nanoframework/Visual-Studio-extension/_apis/build/status/nanoframework.nf-Visual-Studio-extension)](https://dev.azure.com/nanoframework/Visual-Studio-extension/_build/latest?definitionId=17) | [![Visual Studio Marketplace](https://img.shields.io/vscode-marketplace/d/nanoframework.nanoFramework-VS2019-Extension.svg)](https://marketplace.visualstudio.com/items?itemName=nanoframework.nanoFramework-VS2019-Extension) |
-| Visual Studio 2017 extension (:warning: Deprecated) | [![Build Status](https://dev.azure.com/nanoframework/Visual-Studio-extension/_apis/build/status/nanoframework.nf-Visual-Studio-extension)](https://dev.azure.com/nanoframework/Visual-Studio-extension/_build/latest?definitionId=17) | [![Visual Studio Marketplace](https://img.shields.io/vscode-marketplace/d/vs-publisher-1470366.nanoFrameworkVS2017Extension.svg)](https://marketplace.visualstudio.com/items?itemName=vs-publisher-1470366.nanoFrameworkVS2017Extension) |
+| Visual Studio 2022 extension | [![Build Status](https://dev.azure.com/nanoframework/Visual-Studio-extension/_apis/build/status/nanoframework.nf-Visual-Studio-extension)](https://dev.azure.com/nanoframework/Visual-Studio-extension/_build/latest?definitionId=17) | [![Visual Studio Marketplace](https://img.shields.io/vscode-marketplace/d/nanoframework.nanoFramework-VS2022-Extension.svg)](https://marketplace.visualstudio.com/items?itemName=nanoframework.nanoFramework-VS2022-Extension) | [![Open VSIX Gallery](https://img.shields.io/vscode-marketplace/d/nanoframework.nanoFramework-VS2022-Extension.svg)](https://www.vsixgallery.com/extension/bf694e17-fa5f-4877-9317-6d3664b2689a)
+| Visual Studio 2019 extension | [![Build Status](https://dev.azure.com/nanoframework/Visual-Studio-extension/_apis/build/status/nanoframework.nf-Visual-Studio-extension)](https://dev.azure.com/nanoframework/Visual-Studio-extension/_build/latest?definitionId=17) | [![Visual Studio Marketplace](https://img.shields.io/vscode-marketplace/d/nanoframework.nanoFramework-VS2019-Extension.svg)](https://marketplace.visualstudio.com/items?itemName=nanoframework.nanoFramework-VS2019-Extension) | [![Open VSIX Gallery](https://img.shields.io/vscode-marketplace/d/nanoframework.nanoFramework-VS2019-Extension.svg)](https://www.vsixgallery.com/extension/455f2be5-bb07-451e-b351-a9faf3018dc9) |
+| Visual Studio 2017 extension (:warning: Deprecated) | [![Build Status](https://dev.azure.com/nanoframework/Visual-Studio-extension/_apis/build/status/nanoframework.nf-Visual-Studio-extension)](https://dev.azure.com/nanoframework/Visual-Studio-extension/_build/latest?definitionId=17) | [![Visual Studio Marketplace](https://img.shields.io/vscode-marketplace/d/vs-publisher-1470366.nanoFrameworkVS2017Extension.svg)](https://marketplace.visualstudio.com/items?itemName=vs-publisher-1470366.nanoFrameworkVS2017Extension) | | 
 
 ## Feedback and documentation