proof of concept drupal module to address workflow issues needing https://www.drupal.org/project/drupal/issues/2901418
@todo: update readme!
Create hook_deploy_NAME update hooks in mymodule.deploy.php the same way you do with post_update hooks.
Then run drush deploy-hook:run to run all deploy hooks that have not been run yet.
ie the sequence becomes
drush updb -y
drush cim -y
drush deploy-hook:run -y # it currently doesn't ask for confirmation yet
All aspects of this including module name and drush command names are up for debate, feedback welcome!