Remove AppVeyor and Azure DevOps build definitions

Author: christophwille

ICSharpCode.AvalonEdit.Sample/ICSharpCode.AvalonEdit.Sample.csproj

@@ -9,7 +9,7 @@
 	<AssemblyOriginatorKeyFile>..\ICSharpCode.AvalonEdit\ICSharpCode.AvalonEdit.snk</AssemblyOriginatorKeyFile>
     <RootNamespace>AvalonEdit.Sample</RootNamespace>
 	<Company>ic#code</Company>
-    <Copyright>2000-2019 AlphaSierraPapa for the SharpDevelop Team</Copyright>
+    <Copyright>2000-2021 AlphaSierraPapa for the SharpDevelop Team</Copyright>
     <Description>Sample for WPF-based extensible text editor</Description>
 	<IsPackable>false</IsPackable>	
   </PropertyGroup>

ICSharpCode.AvalonEdit/ICSharpCode.AvalonEdit.csproj

@@ -9,7 +9,7 @@
     <AssemblyOriginatorKeyFile>ICSharpCode.AvalonEdit.snk</AssemblyOriginatorKeyFile>
     <DocumentationFile>ICSharpCode.AvalonEdit.xml</DocumentationFile>
     <Company>ic#code</Company>
-    <Copyright>2000-2020 AlphaSierraPapa for the SharpDevelop Team</Copyright>
+    <Copyright>2000-2021 AlphaSierraPapa for the SharpDevelop Team</Copyright>
     <Description>AvalonEdit is the WPF-based text editor used in SharpDevelop. There are three builds of AvalonEdit included in this package: .NET 4.0, 4.5 and .NET Core 3.0.</Description>
     <Version>6.1</Version>
     <AssemblyVersion>6.1.0.0</AssemblyVersion>

README.md

@@ -1,4 +1,4 @@
-# AvalonEdit [![NuGet](https://img.shields.io/nuget/v/AvalonEdit.svg)](https://nuget.org/packages/AvalonEdit) [![Build status](https://ci.appveyor.com/api/projects/status/bvvux3y2b6tw272e/branch/master?svg=true)](https://ci.appveyor.com/project/icsharpcode/avalonedit/branch/master) [![Build Status Azure Pipelines](https://icsharpcode.visualstudio.com/icsharpcode-pipelines/_apis/build/status/icsharpcode.AvalonEdit?branchName=master)](https://icsharpcode.visualstudio.com/icsharpcode-pipelines/_build/latest?definitionId=3&branchName=master)
+# AvalonEdit [![NuGet](https://img.shields.io/nuget/v/AvalonEdit.svg)](https://nuget.org/packages/AvalonEdit) [![Build AvalonEdit](https://github.com/icsharpcode/AvalonEdit/actions/workflows/dotnet.yml/badge.svg)](https://github.com/icsharpcode/AvalonEdit/actions/workflows/dotnet.yml)
 
 
 AvalonEdit is the name of the WPF-based text editor in SharpDevelop 4.x "Mirador" and beyond. It is also being used in ILSpy and many other projects.