returnOriginal flag is deprecated in findOneAndUpdate

[dulacskamty]

Hi!
I really like this great package, thanks for creating that!

However, I got a DeprecationWarning during .get():
"[MONGODB DRIVER] DeprecationWarning: collection.findOneAndUpdate option [returnOriginal] is deprecated and will be removed in a later version".

(Other developers have also experienced this warning with MongoDB driver:
Automattic/mongoose#10285)

This deprecation was introduced in the latest MongoDB driver:
https://jira.mongodb.org/browse/NODE-1812

I thought that maybe you may want to know about this deprecation.