Make sure we keep Annotations in design's proguard

BUG: 24861467

Change-Id: I8ea08f16d3f2422c3b61fab93357806864b2d23e
diff --git a/design/proguard-rules.pro b/design/proguard-rules.pro
index ea77945..96e2ee0 100644
--- a/design/proguard-rules.pro
+++ b/design/proguard-rules.pro
@@ -17,3 +17,6 @@
     public <init>(android.content.Context, android.util.AttributeSet);
     public <init>();
 }
+
+# Make sure we keep annotations for CoordinatorLayout's DefaultBehavior
+-keepattributes *Annotation*