Enabled more optimisation

The APK is so tiny and runs even faster now. How did I not do this earlier?

app/build.gradle

@@ -21,6 +21,7 @@ android {
     buildTypes {
         release {
             minifyEnabled true
+            shrinkResources true
             proguardFiles getDefaultProguardFile('proguard-android-optimize.txt'), 'proguard-rules.pro'
         }
     }

app/src/main/res/raw/keep.xml

@@ -0,0 +1,3 @@
+<?xml version="1.0" encoding="utf-8"?>
+<resources xmlns:tools="http://schemas.android.com/tools"
+           tools:shrinkMode="strict" />

gradle.properties

@@ -22,3 +22,5 @@ kotlin.code.style=official
 # Kapt workaround
 kapt.use.worker.api=false
 kapt.incremental.apt=false
+# R8 optimisation
+android.enableR8.fullMode=true