chore(deps): update reactiveui to 3.1.0 (#927)

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

Author: renovate[bot]

src/samples/Directory.Packages.props

@@ -8,7 +8,7 @@
     <PackageVersion Include="Avalonia.Desktop" Version="12.0.3" />
     <PackageVersion Include="Avalonia.Diagnostics" Version="11.3.17" />
     <PackageVersion Include="MessageBox.Avalonia" Version="12.0.0" />
-    <PackageVersion Include="ReactiveUI.SourceGenerators" Version="3.0.0" />
+    <PackageVersion Include="ReactiveUI.SourceGenerators" Version="3.1.0" />
     <PackageVersion Include="MahApps.Metro" Version="2.4.11" />
     <PackageVersion Include="ReactiveUI.WPF" Version="23.2.28" />
     <PackageVersion Include="ReactiveUI.WinForms" Version="23.2.28" />