System apps must target API 28 or higher

Bug: 120997004
Change-Id: I998a443a4327c47cbab8e4bc4843be1693f05d8d

AndroidManifest.xml

@@ -20,7 +20,7 @@
 <manifest
     xmlns:android="http://schemas.android.com/apk/res/android"
     package="com.android.launcher3">
-    <uses-sdk android:targetSdkVersion="23" android:minSdkVersion="21"/>
+    <uses-sdk android:targetSdkVersion="28" android:minSdkVersion="21"/>
     <!--
     Manifest entries specific to Launcher3. This is merged with AndroidManifest-common.xml.
     Refer comments around specific entries on how to extend individual components.

go/AndroidManifest.xml

@@ -22,7 +22,7 @@
     xmlns:tools="http://schemas.android.com/tools"
     package="com.android.launcher3" >
 
-    <uses-sdk android:targetSdkVersion="23" android:minSdkVersion="21"/>
+    <uses-sdk android:targetSdkVersion="28" android:minSdkVersion="21"/>
 
     <application
         android:backupAgent="com.android.launcher3.LauncherBackupAgent"

tests/AndroidManifest.xml

@@ -18,7 +18,7 @@
     xmlns:tools="http://schemas.android.com/tools"
     package="com.android.launcher3.tests">
 
-    <uses-sdk android:targetSdkVersion="25" android:minSdkVersion="21"
+    <uses-sdk android:targetSdkVersion="28" android:minSdkVersion="21"
               tools:overrideLibrary="android.support.test.uiautomator.v18"/>
 
     <application android:debuggable="true">

tests/dummy_app/AndroidManifest.xml

@@ -21,7 +21,7 @@
      to come from a domain that you own or have control over. -->
 <manifest xmlns:android="http://schemas.android.com/apk/res/android"
     package="com.example.android.aardwolf">
-    <uses-sdk android:targetSdkVersion="25" android:minSdkVersion="21"/>
+    <uses-sdk android:targetSdkVersion="28" android:minSdkVersion="21"/>
     <application android:label="Aardwolf">
         <activity
             android:name="Activity1"