Merge pull request #2887 from AvaloniaUI/update-xamlil

Updated XamlIl: [Flags] and TypeConverterAttribute for properties

src/Markup/Avalonia.Markup.Xaml/XamlIl/CompilerExtensions/Transformers/AvaloniaXamlIlTransformInstanceAttachedProperties.cs

@@ -164,6 +164,8 @@ namespace Avalonia.Markup.Xaml.XamlIl.CompilerExtensions.Transformers
                 public bool IsStatic => true;
                 public string Name { get; protected set; }
                 public IXamlIlType DeclaringType { get; }
+                public IXamlIlMethod MakeGenericMethod(IReadOnlyList<IXamlIlType> typeArguments) 
+                    => throw new System.NotSupportedException();
 
 
                 public bool Equals(IXamlIlMethod other) =>

src/Markup/Avalonia.Markup.Xaml/XamlIl/xamlil.github

@@ -1 +1 @@
-Subproject commit c2ec091f79fb4e1eea629bc823c9c24da7050022
+Subproject commit d3b1f5bafbea93fb70343c76ca53271905976db8