Bump Avalonia.ReactiveUI from 0.10.7 to 0.10.8 (#31)

Bumps [Avalonia.ReactiveUI](https://github.com/AvaloniaUI/Avalonia) from 0.10.7 to 0.10.8.
- [Release notes](https://github.com/AvaloniaUI/Avalonia/releases)
- [Commits](AvaloniaUI/Avalonia@0.10.7...0.10.8)

---
updated-dependencies:
- dependency-name: Avalonia.ReactiveUI
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <support@github.com>

Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

src/Citrus.Avalonia.Sandbox/Citrus.Avalonia.Sandbox.csproj

@@ -9,7 +9,7 @@
 
   <ItemGroup>
     <PackageReference Include="Avalonia" Version="0.10.8" />
-    <PackageReference Include="Avalonia.ReactiveUI" Version="0.10.7" />
+    <PackageReference Include="Avalonia.ReactiveUI" Version="0.10.8" />
     <PackageReference Include="Avalonia.LinuxFramebuffer" Version="0.10.7" />
     <PackageReference Include="Avalonia.Desktop" Version="0.10.7" />
     <PackageReference Include="ReactiveUI.Validation" Version="2.2.1" />