Add iOS 18's Dark Mode App Icon Asset

This is from utmapp#6428 which requests support for iOS 18's dark icon. Simply added a new image to the `AppIcon` asset catalog that is a transparent, color inverted version of the UTM logo.

Platform/Assets.xcassets/AppIcon.appiconset/Contents.json

@@ -1,116 +1,128 @@
 {
   "images" : [
     {
-      "size" : "20x20",
-      "idiom" : "iphone",
-      "filename" : "icon_20pt@2x.png",
-      "scale" : "2x"
+      "appearances" : [
+        {
+          "appearance" : "luminosity",
+          "value" : "dark"
+        }
+      ],
+      "filename" : "icon_dark.png",
+      "idiom" : "universal",
+      "platform" : "ios",
+      "size" : "1024x1024"
     },
     {
-      "size" : "20x20",
+      "filename" : "icon_20pt@2x.png",
       "idiom" : "iphone",
-      "filename" : "icon_20pt@3x.png",
-      "scale" : "3x"
+      "scale" : "2x",
+      "size" : "20x20"
     },
     {
-      "size" : "29x29",
+      "filename" : "icon_20pt@3x.png",
       "idiom" : "iphone",
-      "filename" : "icon_29pt@2x.png",
-      "scale" : "2x"
+      "scale" : "3x",
+      "size" : "20x20"
     },
     {
-      "size" : "29x29",
+      "filename" : "icon_29pt@2x.png",
       "idiom" : "iphone",
-      "filename" : "icon_29pt@3x.png",
-      "scale" : "3x"
+      "scale" : "2x",
+      "size" : "29x29"
     },
     {
-      "size" : "40x40",
+      "filename" : "icon_29pt@3x.png",
       "idiom" : "iphone",
-      "filename" : "icon_40pt@2x.png",
-      "scale" : "2x"
+      "scale" : "3x",
+      "size" : "29x29"
     },
     {
-      "size" : "40x40",
+      "filename" : "icon_40pt@2x.png",
       "idiom" : "iphone",
-      "filename" : "icon_40pt@3x.png",
-      "scale" : "3x"
+      "scale" : "2x",
+      "size" : "40x40"
     },
     {
-      "size" : "60x60",
+      "filename" : "icon_40pt@3x.png",
       "idiom" : "iphone",
-      "filename" : "icon_60pt@2x.png",
-      "scale" : "2x"
+      "scale" : "3x",
+      "size" : "40x40"
     },
     {
-      "size" : "60x60",
+      "filename" : "icon_60pt@2x.png",
       "idiom" : "iphone",
+      "scale" : "2x",
+      "size" : "60x60"
+    },
+    {
       "filename" : "icon_60pt@3x.png",
-      "scale" : "3x"
+      "idiom" : "iphone",
+      "scale" : "3x",
+      "size" : "60x60"
     },
     {
-      "size" : "20x20",
-      "idiom" : "ipad",
       "filename" : "icon_20pt.png",
-      "scale" : "1x"
+      "idiom" : "ipad",
+      "scale" : "1x",
+      "size" : "20x20"
     },
     {
-      "size" : "20x20",
-      "idiom" : "ipad",
       "filename" : "icon_20pt@2x-1.png",
-      "scale" : "2x"
+      "idiom" : "ipad",
+      "scale" : "2x",
+      "size" : "20x20"
     },
     {
-      "size" : "29x29",
-      "idiom" : "ipad",
       "filename" : "icon_29pt.png",
-      "scale" : "1x"
+      "idiom" : "ipad",
+      "scale" : "1x",
+      "size" : "29x29"
     },
     {
-      "size" : "29x29",
-      "idiom" : "ipad",
       "filename" : "icon_29pt@2x-1.png",
-      "scale" : "2x"
+      "idiom" : "ipad",
+      "scale" : "2x",
+      "size" : "29x29"
     },
     {
-      "size" : "40x40",
-      "idiom" : "ipad",
       "filename" : "icon_40pt.png",
-      "scale" : "1x"
+      "idiom" : "ipad",
+      "scale" : "1x",
+      "size" : "40x40"
     },
     {
-      "size" : "40x40",
-      "idiom" : "ipad",
       "filename" : "icon_40pt@2x-1.png",
-      "scale" : "2x"
+      "idiom" : "ipad",
+      "scale" : "2x",
+      "size" : "40x40"
     },
     {
-      "size" : "76x76",
-      "idiom" : "ipad",
       "filename" : "icon_76pt.png",
-      "scale" : "1x"
+      "idiom" : "ipad",
+      "scale" : "1x",
+      "size" : "76x76"
     },
     {
-      "size" : "76x76",
-      "idiom" : "ipad",
       "filename" : "icon_76pt@2x.png",
-      "scale" : "2x"
+      "idiom" : "ipad",
+      "scale" : "2x",
+      "size" : "76x76"
     },
     {
-      "size" : "83.5x83.5",
-      "idiom" : "ipad",
       "filename" : "icon_83.5@2x.png",
-      "scale" : "2x"
+      "idiom" : "ipad",
+      "scale" : "2x",
+      "size" : "83.5x83.5"
     },
     {
-      "size" : "1024x1024",
-      "idiom" : "ios-marketing",
       "filename" : "Icon.png",
-      "scale" : "1x"
+      "idiom" : "ios-marketing",
+      "scale" : "1x",
+      "size" : "1024x1024"
     }
   ],
   "info" : {
-    "version" : 1,
-    "author" : "xcode"
+    "author" : "xcode",
+    "version" : 1
   }
-}
+}