Upgrading from version 1.x fails

Problem/Motivation

Updating from version 1.x fails with the following error on update 8200.
You have requested a non-existent service "externalauth.authmap"

This is because the services used in 8200 now use the externalauth module, but that module is only enabled in update 8203.

Steps to reproduce

Run an update from a site running version 1.x of the module.

Proposed resolution

Create an update hook 8198 that enables the module prior to it's use in 8200.