Enable debuggable in Android

Author: daemyung

android/app/build.gradle

@@ -23,7 +23,7 @@ android {
     }
     externalNativeBuild {
         cmake {
-            version '3.15.5'
+            version '3.16.2'
             path '../../../CMakeLists.txt'
         }
     }

android/app/src/main/AndroidManifest.xml

@@ -11,7 +11,8 @@
       android:fullBackupContent="false"
       android:icon="@mipmap/ic_launcher"
       android:label="@string/app_name"
-      android:hasCode="false">
+      android:hasCode="false"
+      android:debuggable="true">
 
     <!-- Our activity is the built-in NativeActivity framework class.
          This will take care of integrating with our NDK code. -->