build(deps): bump Citrus.Avalonia and Avalonia in /Sample (#729)

Bumps [Citrus.Avalonia](https://github.com/worldbeater/citrus.avalonia) and [Avalonia](https://github.com/AvaloniaUI/Avalonia). These dependencies needed to be updated together.

Updates `Citrus.Avalonia` from 1.6.1 to 2.1.1
- [Release notes](https://github.com/worldbeater/citrus.avalonia/releases)
- [Commits](AvaloniaUI/Citrus.Avalonia@1.6.1...2.1.1)

Updates `Avalonia` from 0.10.12 to 11.0.0
- [Release notes](https://github.com/AvaloniaUI/Avalonia/releases)
- [Commits](AvaloniaUI/Avalonia@0.10.12...11.0.0)

---
updated-dependencies:
- dependency-name: Citrus.Avalonia
  dependency-type: direct:production
  update-type: version-update:semver-major
- dependency-name: Avalonia
  dependency-type: direct:production
  update-type: version-update:semver-major
...

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

Sample/SextantSample.Avalonia/SextantSample.Avalonia.csproj

@@ -4,7 +4,7 @@
         <TargetFramework>netcoreapp3.1</TargetFramework>
     </PropertyGroup>
     <ItemGroup>
-        <PackageReference Include="Citrus.Avalonia" Version="1.6.1" />
+        <PackageReference Include="Citrus.Avalonia" Version="2.1.1" />
         <PackageReference Include="MessageBox.Avalonia" Version="3.1.5.1" />
     </ItemGroup>
     <ItemGroup>