chore(Assistant v2): Apply manual changes

Author: lpatino10

assistant/src/main/java/com/ibm/watson/assistant/v2/Assistant.java

@@ -41,7 +41,7 @@
  */
 public class Assistant extends BaseService {
 
-  private static final String DEFAULT_SERVICE_NAME = "conversation";
+  private static final String DEFAULT_SERVICE_NAME = "assistant";
 
   private static final String DEFAULT_SERVICE_URL = "https://gateway.watsonplatform.net/assistant/api";