API level 30 upgrade: AOSP/Launcher3

The AndroidManifest.xml and build.gradle file of the AOSP
Launcher app has been upgraded so that its targetSdkVersion
is 30. This change has been made on git_master so that
we can avoid presubmit conflicts when making this change
on the aosp-master branch.

Change-Id: Ie476f8cbe56bf51218b15b8361a22fec2dc845e6
(cherry picked from commit 499ffce2e704aa82b4d10468f99afd3dc4e727f8)
diff --git a/build.gradle b/build.gradle
index a7eef13..0622d87 100644
--- a/build.gradle
+++ b/build.gradle
@@ -21,8 +21,8 @@
     buildToolsVersion BUILD_TOOLS_VERSION
 
     defaultConfig {
-        minSdkVersion 25
-        targetSdkVersion 28
+        minSdkVersion 26
+        targetSdkVersion 30
         versionCode 1
         versionName "1.0"