Add MyGet badge in README

Author: AndreyAkinshin

README.md

@@ -7,6 +7,7 @@
 <div align="center">
 
   [![NuGet](https://img.shields.io/nuget/v/BenchmarkDotNet.svg)](https://www.nuget.org/packages/BenchmarkDotNet/)
+  [![MyGet](https://img.shields.io/myget/benchmarkdotnet/vpre/benchmarkdotnet?label=myget)](https://www.myget.org/feed/Packages/benchmarkdotnet)
   [![Downloads](https://img.shields.io/nuget/dt/benchmarkdotnet.svg)](https://www.nuget.org/packages/BenchmarkDotNet/)
   [![Stars](https://img.shields.io/github/stars/dotnet/BenchmarkDotNet?color=brightgreen)](https://github.com/dotnet/BenchmarkDotNet/stargazers)
   ![License](https://img.shields.io/badge/license-MIT-blue.svg)