Which table stores info about hook_update_N?
The schema version for the update hook is stored in the key_value table.

You can set it with the global function drupal_set_installed_schema_version($module, $version).

For example:

drupal_set_installed_schema_version('my_module', 8005);


If you want the check the schema version number:

$schema_version = drupal_get_installed_schema_version('my_module');