Sets up R8

Change-Id: I7d3a115f68e0826794a0344507b25d601874f34a

Author: JoseAlcerreca

app/build.gradle

@@ -32,14 +32,13 @@ android {
         debug {
             minifyEnabled false
             testCoverageEnabled true
-            useProguard false
             proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
             testProguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguardTest-rules.pro'
         }
 
         release {
             minifyEnabled true
-            useProguard true
+            shrinkResources true
             proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
             testProguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguardTest-rules.pro'
         }

gradle.properties

@@ -18,4 +18,5 @@
 # org.gradle.parallel=true
 android.enableJetifier=true
 android.useAndroidX=true
-android.enableUnitTestBinaryResources=true
+android.enableUnitTestBinaryResources=true
+android.enableR8=true