Re-enable minification and add a custom proguard-android-optimize ruleset

Signed-off-by: Harsh Shandilya <me@msfjarvis.dev>

build.gradle

@@ -96,8 +96,10 @@ android {
         }
 
         release {
+            minifyEnabled true
             shrinkResources true
             versionNameSuffix ".release"
+            proguardFiles "proguard-android-optimize.txt", "proguard.flags"
         }
     }
 

proguard-android-optimize.txt

@@ -0,0 +1,36 @@
+-allowaccessmodification
+-dontpreverify
+-dontusemixedcaseclassnames
+-dontskipnonpubliclibraryclasses
+-verbose
+
+-keepattributes *Annotation*
+
+-keepclasseswithmembernames class * {
+    native <methods>;
+}
+
+-keepclassmembers enum * {
+    public static **[] values();
+    public static ** valueOf(java.lang.String);
+}
+
+-keepclassmembers class * implements android.os.Parcelable {
+  public static final ** CREATOR;
+}
+
+-keep class androidx.annotation.Keep
+
+-keep @androidx.annotation.Keep class * {*;}
+
+-keepclasseswithmembers class * {
+    @androidx.annotation.Keep <methods>;
+}
+
+-keepclasseswithmembers class * {
+    @androidx.annotation.Keep <fields>;
+}
+
+-keepclasseswithmembers class * {
+    @androidx.annotation.Keep <init>(...);
+}