Merge pull request #271 from Iterable/MOB-2217-expires-at

[MOB-2217] make getExpiresAt() public

Author: roninopf

iterableapi/src/main/java/com/iterable/iterableapi/IterableInAppMessage.java

@@ -215,7 +215,7 @@ public Date getCreatedAt() {
     }
 
     @NonNull
-    Date getExpiresAt() {
+    public Date getExpiresAt() {
         return expiresAt;
     }