Adding code length for verify session request

lib/resources/verify.js

@@ -140,7 +140,7 @@ export class SessionInterface extends PlivoResourceInterface {
   create(sessionReq){
 
     var isObject = arguments.length;
-    var app_uuid, recipient, url, method, channel, locale , brand_name, app_hash 
+    var app_uuid, recipient, url, method, channel, locale , brand_name, app_hash , code_length
 
     if (isObject === 1) {
       app_uuid = sessionReq.app_uuid
@@ -151,6 +151,7 @@ export class SessionInterface extends PlivoResourceInterface {
       locale = sessionReq.locale
       brand_name = sessionReq.brand_name
       app_hash = sessionReq.app_hash
+      code_length = sessionReq.code_length
     }
 
     let errors = validate([{
@@ -190,6 +191,9 @@ export class SessionInterface extends PlivoResourceInterface {
       if(app_hash) {
         params.app_hash = app_hash
       }
+      if (code_length) {
+        params.code_length = code_length
+      }
     }
 
     let client = this[clientKey];