Fix CPM merge error (#2321)

Author: ViktorHofer

Directory.Build.targets

@@ -9,8 +9,8 @@
   </PropertyGroup>
 
   <ItemGroup Condition="'$(DisableArcade)' == '1' and $(MSBuildProjectName.EndsWith('.Tests'))">
-    <PackageReference Include="xunit" Version="2.4.1" />
-    <PackageReference Include="xunit.runner.visualstudio" Version="2.4.1" />
+    <PackageReference Include="xunit" />
+    <PackageReference Include="xunit.runner.visualstudio" />
   </ItemGroup>
 
-</Project>
+</Project>