Update readme.md

We don't maintain this build feed anymore so the badge is redundant.

readme.md

@@ -1,7 +1,7 @@
 [![Telegram](https://raw.githubusercontent.com/Patrolavia/telegram-badge/master/chat.svg)](https://t.me/Avalonia)
 [![Gitter](https://badges.gitter.im/Join%20Chat.svg)](https://gitter.im/AvaloniaUI/Avalonia?utm_campaign=pr-badge&utm_content=badge&utm_medium=badge&utm_source=badge) [![Discord](https://img.shields.io/badge/discord-join%20chat-46BC99)]( https://aka.ms/dotnet-discord) [![Build Status](https://dev.azure.com/AvaloniaUI/AvaloniaUI/_apis/build/status/AvaloniaUI.Avalonia)](https://dev.azure.com/AvaloniaUI/AvaloniaUI/_build/latest?definitionId=4) [![Backers on Open Collective](https://opencollective.com/Avalonia/backers/badge.svg)](#backers) [![Sponsors on Open Collective](https://opencollective.com/Avalonia/sponsors/badge.svg)](#sponsors) ![License](https://img.shields.io/github/license/avaloniaui/avalonia.svg)
 <br />
-[![NuGet](https://img.shields.io/nuget/v/Avalonia.svg)](https://www.nuget.org/packages/Avalonia) [![downloads](https://img.shields.io/nuget/dt/avalonia)](https://www.nuget.org/packages/Avalonia) [![MyGet](https://img.shields.io/myget/avalonia-ci/vpre/Avalonia.svg?label=myget)](https://www.myget.org/gallery/avalonia-ci) ![Size](https://img.shields.io/github/repo-size/avaloniaui/avalonia.svg) 
+[![NuGet](https://img.shields.io/nuget/v/Avalonia.svg)](https://www.nuget.org/packages/Avalonia) [![downloads](https://img.shields.io/nuget/dt/avalonia)](https://www.nuget.org/packages/Avalonia)  ![Size](https://img.shields.io/github/repo-size/avaloniaui/avalonia.svg) 
 
 ## 📖 About