Update dependency xunit.runner.visualstudio to v2.8.0

Author: renovate[bot]

Directory.Build.props

@@ -50,7 +50,7 @@
   <ItemGroup Condition="'$(IsTestProject)' == 'true'">
     <PackageReference Include="Microsoft.NET.Test.Sdk" Version="17.9.0" />
     <PackageReference Include="xunit" Version="2.8.0" />
-    <PackageReference Include="xunit.runner.visualstudio" Version="2.5.7">
+    <PackageReference Include="xunit.runner.visualstudio" Version="2.8.0">
       <IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>
       <PrivateAssets>all</PrivateAssets>
     </PackageReference>