Update Language.java

Author: tanmayb123

src/main/java/com/ibm/watson/developer_cloud/language_translation/v2/model/Language.java

@@ -16,7 +16,7 @@ public String toString() {
         case PORTUGESE: return "pt";
       }
     } else {
-      return super.toString();
+      return super.toString().toLowerCase();
     }
     return "";
   }