D11 compatibility

Problem/Motivation

I'd like to upgrade my site but Entity Limit does not support D11.

Upgrade Status module scan reports 2 issues, both usages of user_roles().

Call to deprecated function user_roles(). Deprecated in drupal:10.2.0 and is removed from drupal:11.0.0. Use Drupal\user\Entity\Role::loadMultiple() and, if necessary, an inline implementation instead.