Update: the connection name is now a required parameter in Zoho Books integration tasks. Look at this announcement from Zoho for more details and view the updateRecord integration task.
So, your code would look more like this: updateCustomer = zoho.books.updateRecord(“Contacts”, orgId, customerMap, “connection_name”);
(You’ll have to create your own connection from Zoho Books….to itself, from Zoho Books)