chore(deps): update xunit-dotnet monorepo to v2.8.1 (#97)

Co-authored-by: renovate[bot] <29139614+renovate[bot]@users.noreply.github.com>

Author: renovate[bot]

src/ReactiveMvvm.Tests/ReactiveMvvm.Tests.csproj

@@ -14,8 +14,8 @@
     <PackageReference Include="Microsoft.NET.Test.Sdk" Version="17.9.0" />
     <PackageReference Include="NSubstitute" Version="5.1.0" />
     <PackageReference Include="ReactiveUI.Testing" Version="20.0.1" />
-    <PackageReference Include="xunit" Version="2.8.0" />
-    <PackageReference Include="xunit.runner.visualstudio" Version="2.8.0">
+    <PackageReference Include="xunit" Version="2.8.1" />
+    <PackageReference Include="xunit.runner.visualstudio" Version="2.8.1">
       <PrivateAssets>all</PrivateAssets>
       <IncludeAssets>runtime; build; native; contentfiles; analyzers</IncludeAssets>
     </PackageReference>