chore(deps): update reactiveui to v21 (#277)

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

Directory.Packages.props

@@ -12,9 +12,9 @@
     <PackageVersion Include="MSTest.TestAdapter" Version="3.10.4" />
     <PackageVersion Include="MSTest.TestFramework" Version="3.10.4" />
     <PackageVersion Include="ReactiveMarbles.ObservableEvents.SourceGenerator" Version="1.3.1" />
-    <PackageVersion Include="ReactiveUI" Version="20.4.1" />
+    <PackageVersion Include="ReactiveUI" Version="21.0.1" />
     <PackageVersion Include="ReactiveUI.SourceGenerators" Version="2.3.1" />
-    <PackageVersion Include="ReactiveUI.WPF" Version="20.4.1" />
+    <PackageVersion Include="ReactiveUI.WPF" Version="21.0.1" />
     <PackageVersion Include="Socks5" Version="1.0.2" />
     <PackageVersion Include="Splat.Microsoft.Extensions.DependencyInjection" Version="16.1.1" />
     <PackageVersion Include="Volo.Abp.Autofac" Version="9.3.2" />