Update to XUnit v3

Author: Numpsy

src/Avalonia.FuncUI.UnitTests/Avalonia.FuncUI.UnitTests.fsproj

@@ -18,17 +18,16 @@
     <Compile Include="VirtualDom\VirtualDom.PatcherTests.fs" />
     <Compile Include="DSL\Base\StyledElementTests.fs" />
     <Compile Include="State.fs" />
-    <Compile Include="Program.fs" />
   </ItemGroup>
 
   <ItemGroup>
-    <PackageReference Include="Microsoft.NET.Test.Sdk" Version="17.10.0" />
+    <PackageReference Include="Microsoft.NET.Test.Sdk" Version="17.14.1" />
     <PackageReference Include="System.Reactive" Version="6.0.1" />
-    <PackageReference Include="xunit" Version="2.9.0" />
-    <PackageReference Include="xunit.runner.visualstudio" Version="2.8.2">
+    <PackageReference Include="xunit.runner.visualstudio" Version="3.1.1">
       <PrivateAssets>all</PrivateAssets>
       <IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>
     </PackageReference>
+    <PackageReference Include="xunit.v3" Version="2.0.3" />
   </ItemGroup>
 
   <ItemGroup>