build: Splash screen set up for iOS and Android

Author: Axeloooo

android/app/src/main/res/mipmap-hdpi/splash.png

@@ -4,7 +4,7 @@
     <style name="LaunchTheme" parent="@android:style/Theme.Black.NoTitleBar">
         <!-- Show a splash screen on the activity. Automatically removed when
              the Flutter engine draws its first frame -->
-        <item name="android:windowBackground">@drawable/launch_background</item>
+        <item name="android:windowBackground">@mipmap/splash</item>
     </style>
     <!-- Theme applied to the Android Window as soon as the process has started.
          This theme determines the color of the Android Window while your

android/app/src/main/res/mipmap-mdpi/splash.png

@@ -4,7 +4,7 @@
     <style name="LaunchTheme" parent="@android:style/Theme.Light.NoTitleBar">
         <!-- Show a splash screen on the activity. Automatically removed when
              the Flutter engine draws its first frame -->
-        <item name="android:windowBackground">@drawable/launch_background</item>
+        <item name="android:windowBackground">@mipmap/splash</item>
     </style>
     <!-- Theme applied to the Android Window as soon as the process has started.
          This theme determines the color of the Android Window while your

android/app/src/main/res/mipmap-xhdpi/splash.png

@@ -1,23 +1,23 @@
 {
   "images" : [
     {
+      "filename" : "SplashScreen.png",
       "idiom" : "universal",
-      "filename" : "LaunchImage.png",
       "scale" : "1x"
     },
     {
+      "filename" : "[email protected]",
       "idiom" : "universal",
-      "filename" : "[email protected]",
       "scale" : "2x"
     },
     {
+      "filename" : "[email protected]",
       "idiom" : "universal",
-      "filename" : "[email protected]",
       "scale" : "3x"
     }
   ],
   "info" : {
-    "version" : 1,
-    "author" : "xcode"
+    "author" : "xcode",
+    "version" : 1
   }
 }