try a new date format

Author: germanattanasio

src/main/java/com/ibm/watson/developer_cloud/util/GsonSingleton.java

@@ -24,7 +24,7 @@
 public class GsonSingleton {
 
 	/** The Constant DATE_FORMAT_UTC. */
-	private static final String DATE_FORMAT_UTC = "yyyy-MM-dd'T'HH:mm:ss.SSS'Z'";
+	private static final String DATE_FORMAT_UTC = "yyyy-MM-dd'T'HH:mm:ss.SSSXXX";
 	/** The gson. */
 	private static Gson gson;