Mosh suggests to not insert the Update method in Repository Pattern, maybe I have lost something, but how can I update data without that method?
Repositories behave just like collections. To update an object in a collection you retrieve it from the collection and change its properties.
So to update data you retrieve the object to change from the repository and change it. The changes are persisted to the database when calling Complete() on the UnitOfWork (which calls SaveChanges() on the DbContext).