chore(deps): update dependency verify.xunit to 28.4.0

Author: renovate[bot]

src/ReactiveUI.Validation.Tests/ReactiveUI.Validation.Tests.csproj

@@ -16,7 +16,7 @@
     <PackageReference Include="Xunit.StaFact" Version="1.1.11" />
     <PackageReference Include="Microsoft.Reactive.Testing" Version="6.0.1" />
     <PackageReference Include="PublicApiGenerator" Version="11.1.0" />
-    <PackageReference Include="Verify.Xunit" Version="28.1.3" />
+    <PackageReference Include="Verify.Xunit" Version="28.4.0" />
     <PackageReference Include="xunit.runner.visualstudio" Version="2.8.2" />
     <PackageReference Include="coverlet.msbuild" Version="6.0.2">
       <PrivateAssets>all</PrivateAssets>