[WEEX-656][iOS] WeexDemo Supporting iPhone XS Max and XR

WeexSDK.podspec

@@ -3,7 +3,7 @@ Pod::Spec.new do |s|
 
   s.name         = "WeexSDK"
 
-  s.version      = "0.18.0"
+  s.version      = "0.19.0"
 
   s.summary      = "WeexSDK Source ."
 

ios/playground/WeexDemo/Assets.xcassets/LaunchImage.launchimage/Contents.json

@@ -1,5 +1,23 @@
 {
   "images" : [
+    {
+      "extent" : "full-screen",
+      "idiom" : "iphone",
+      "subtype" : "2688h",
+      "filename" : "[email protected]",
+      "minimum-system-version" : "12.0",
+      "orientation" : "portrait",
+      "scale" : "3x"
+    },
+    {
+      "extent" : "full-screen",
+      "idiom" : "iphone",
+      "subtype" : "1792h",
+      "filename" : "[email protected]",
+      "minimum-system-version" : "12.0",
+      "orientation" : "portrait",
+      "scale" : "2x"
+    },
     {
       "extent" : "full-screen",
       "idiom" : "iphone",