Update README.md

Author: KirillOsenkov

README.md

@@ -1,6 +1,8 @@
 # http://quickinfo.io
 Extensible set of little one-off features that Google or Bing are missing, such as color and unit conversions, etc.
 
+[![NuGet package](https://img.shields.io/nuget/v/GuiLabs.QuickInfo.svg)](https://nuget.org/packages/GuiLabs.QuickInfo)
+
 ![screenshot](https://github.com/KirillOsenkov/QuickInfo/raw/master/docs/Demo.gif)
 
 ## Motivation