Revert "Update to targetSdkVersion 32."

This reverts commit 7451ee1403.

build.gradle

@@ -28,10 +28,10 @@ buildscript {
 }
 
 ext {
-    BUILD_TOOL_VERSION = '32.0.0'
+    BUILD_TOOL_VERSION = '31.0.0'
 
     COMPILE_SDK = 32
-    TARGET_SDK  = 32
+    TARGET_SDK  = 30
     MINIMUM_SDK = 19
 
     JAVA_VERSION = JavaVersion.VERSION_1_8