Bump Avalonia and Avalonia.Themes.Fluent

Bumps Avalonia from 12.0.4 to 12.1.3
Bumps Avalonia.Themes.Fluent from 12.0.4 to 12.1.3

---
updated-dependencies:
- dependency-name: Avalonia
  dependency-version: 12.1.3
  dependency-type: direct:production
  update-type: version-update:semver-minor
- dependency-name: Avalonia.Themes.Fluent
  dependency-version: 12.1.3
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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

StarterNG/StarterNG.csproj

@@ -24,9 +24,9 @@
     </PropertyGroup>
 
     <ItemGroup>
-        <PackageReference Include="Avalonia" Version="12.0.4" />
+        <PackageReference Include="Avalonia" Version="12.1.3" />
         <PackageReference Include="Avalonia.Desktop" Version="12.0.4" />
-        <PackageReference Include="Avalonia.Themes.Fluent" Version="12.0.4" />
+        <PackageReference Include="Avalonia.Themes.Fluent" Version="12.1.3" />
         <PackageReference Include="Avalonia.Fonts.Inter" Version="12.0.4" />
         <!--Condition below is needed to remove Avalonia.Diagnostics package from build output in Release configuration.-->
         <PackageReference Include="Avalonia.Diagnostics" Version="11.3.17">