Undefined function decoupled_auth_install_update_user_admin_people_view

I cant actually see what change you made in that fork, but I assume you mean change:

Drupal::moduleHandler()->loadInclude('install', 'decoupled_auth', 'decoupled_auth');

This has actually already been fixed in the 2.x and 3.x branches. Which branch are you trying to install?

Hi yanniboi → ,

I haven't pushed anything yet. I'm using release 2.0.0.

Is this duplicated?

Confirmed it is fixed in release 3.0.1