Twelve: Enable code & resource shrinking in gradle too

Change-Id: Ic214eba55c6d57f97bbcc625d234537905c6f6d5
diff --git a/app/build.gradle.kts b/app/build.gradle.kts
index 5f26b41..ad5fd20 100644
--- a/app/build.gradle.kts
+++ b/app/build.gradle.kts
@@ -48,7 +48,12 @@
 
     buildTypes {
         release {
-            isMinifyEnabled = false
+            // Enables code shrinking, obfuscation, and optimization.
+            isMinifyEnabled = true
+
+            // Enables resource shrinking.
+            isShrinkResources = true
+
             proguardFiles(
                 getDefaultProguardFile("proguard-android-optimize.txt"),
                 "proguard-rules.pro"