update gradle

Change-Id: I9647d0bd78568ce8cc5f3935bd0ed9ccc5e390da
diff --git a/ring-android/app/proguard-rules.pro b/ring-android/app/proguard-rules.pro
index fffa5f3..12dd49c 100644
--- a/ring-android/app/proguard-rules.pro
+++ b/ring-android/app/proguard-rules.pro
@@ -2,11 +2,15 @@
   public <init>(android.content.Context);
 }
 
--keepattributes Signature
+-keepattributes InnerClasses
 
 -keep class android.support.v7.widget.LinearLayoutManager { *; }
 -keep,includedescriptorclasses class androidx.core.content.FileProvider { *; }
 
+-keepnames class * implements android.os.Parcelable {
+    public static final ** CREATOR;
+}
+
 -keep,includedescriptorclasses class cx.ring.** { *; }
 -keepclassmembers class cx.ring.** { *; }