Bump targetSdkVersion to "30"

With this CL, versionCode, targetSdkVersion and minSdkVersion will be
bumped/set as follows:

       versionCode: 28 -> 30
  targetSdkVersion: 28 -> 30
     minSdkVersion: 21

As far as we know, there should be no user-visible behavior change on
supported OS versions.

Fix: 189558760
Test: manually verified that LatinIME still is functional
Change-Id: I4bf7588c62fb77bf78d4afcb665e9bfbbef53966
diff --git a/tests/Android.bp b/tests/Android.bp
index e1db354..4c5b74a 100644
--- a/tests/Android.bp
+++ b/tests/Android.bp
@@ -50,6 +50,6 @@
     instrumentation_for: "LatinIME",
 
     min_sdk_version: "14",
-    target_sdk_version: "21",
+    target_sdk_version: "30",
     sdk_version: "current",
 }