fixed target SDK in debug sample

Author: codeanticode

mode/libraries/ar/examples/Cubes/AndroidManifest.xml

@@ -1,6 +1,6 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <manifest xmlns:android="http://schemas.android.com/apk/res/android" xmlns:tools="http://schemas.android.com/tools" android:versionCode="1" android:versionName="1.0" package="">
-    <uses-sdk android:minSdkVersion="24" android:targetSdkVersion="26"/>
+    <uses-sdk android:minSdkVersion="24" android:targetSdkVersion="28"/>
     <uses-permission android:name="android.permission.CAMERA"/>
     <uses-feature android:name="android.hardware.camera.ar" android:required="true"/>
     <uses-feature android:glEsVersion="0x00020000" android:required="true"/>