Bump ReactiveUI.Validation from 2.1.1 to 2.2.1 (#23)

Bumps [ReactiveUI.Validation](https://github.com/reactiveui/reactiveui.validation) from 2.1.1 to 2.2.1.
- [Release notes](https://github.com/reactiveui/reactiveui.validation/releases)
- [Commits](reactiveui/ReactiveUI.Validation@2.1.1...2.2.1)

---
updated-dependencies:
- dependency-name: ReactiveUI.Validation
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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

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

Live.Avalonia.Sample.Library/Live.Avalonia.Sample.Library.csproj

@@ -4,7 +4,7 @@
         <IsPackable>false</IsPackable>
     </PropertyGroup>
     <ItemGroup>
-        <PackageReference Include="ReactiveUI.Validation" Version="2.1.1" />
+        <PackageReference Include="ReactiveUI.Validation" Version="2.2.1" />
         <PackageReference Include="ReactiveUI.Fody" Version="16.2.6" />
     </ItemGroup>
 </Project>