Support Flutter 3.16

Author: mono0926

example/macos/Flutter/GeneratedPluginRegistrant.swift

@@ -5,13 +5,15 @@
 import FlutterMacOS
 import Foundation
 
+import appkit_ui_element_colors
 import dynamic_color
 import file_selector_macos
 import macos_ui
 import macos_window_utils
 import url_launcher_macos
 
 func RegisterGeneratedPlugins(registry: FlutterPluginRegistry) {
+  AppkitUiElementColorsPlugin.register(with: registry.registrar(forPlugin: "AppkitUiElementColorsPlugin"))
   DynamicColorPlugin.register(with: registry.registrar(forPlugin: "DynamicColorPlugin"))
   FileSelectorPlugin.register(with: registry.registrar(forPlugin: "FileSelectorPlugin"))
   MacOSUiPlugin.register(with: registry.registrar(forPlugin: "MacOSUiPlugin"))