[Content]: Add a section on the possibility to update user's email address with new_email field

[querbesd]

What article on segment.com/docs is affected?

https://segment.com/docs/connections/destinations/catalog/drip/

What part(s) of the article would you like to see updated?

The identity part could be updated by mentioning the 'new_email' trait that corresponds to the last email provided by the user (with 'email' being the first email address the customer subscribed the service with).

You can check drip documentation: https://developer.drip.com/#subscribers

Additional information

No response

[github-actions]

This issue is stale because it has been open 60 days with no activity.