Update avalonia monorepo to v12

Author: renovate[bot]

Directory.Packages.props

@@ -5,11 +5,11 @@
   </PropertyGroup>
   <ItemGroup>
     <PackageVersion Include="ApprovalTests" Version="6.0.0" />
-    <PackageVersion Include="Avalonia" Version="[11.0.0,12.0.0)" />
-    <PackageVersion Include="Avalonia.Desktop" Version="11.3.14" />
+    <PackageVersion Include="Avalonia" Version="[11.0.0,12.0.1]" />
+    <PackageVersion Include="Avalonia.Desktop" Version="12.0.1" />
     <PackageVersion Include="Avalonia.Diagnostics" Version="11.3.14" />
     <PackageVersion Include="Avalonia.ReactiveUI" Version="11.3.9" />
-    <PackageVersion Include="Avalonia.Themes.Fluent" Version="11.3.14" />
+    <PackageVersion Include="Avalonia.Themes.Fluent" Version="12.0.1" />
     <PackageVersion Include="ChangelogAutomation.MSBuild" Version="3.0.5" />
     <PackageVersion Include="Foq" Version="1.8.0" />
     <PackageVersion Include="FSharp.Core" Version="$(FSCorePackageVersion)" />