chore(deps): update dependency reactiveui.testing to 20.4.1 (#108)

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

Author: renovate[bot]

src/directory.packages.props

@@ -29,7 +29,7 @@
     <PackageVersion Include="coverlet.msbuild" Version="6.0.4" />
     <PackageVersion Include="FluentAssertions" Version="8.4.0" />
     <PackageVersion Include="FluentAssertions.Analyzers" Version="0.34.1" />
-    <PackageVersion Include="ReactiveUI.Testing" Version="20.3.1" />
+    <PackageVersion Include="ReactiveUI.Testing" Version="20.4.1" />
     <PackageVersion Include="Microsoft.NET.Test.Sdk" Version="17.14.1" />
     <PackageVersion Include="Microsoft.Reactive.Testing" Version="6.0.1" />
   </ItemGroup>