Routes.php uses a deprecated and removed function:
Call to deprecated method entityManager() of class Drupal. Deprecated in drupal:8.0.0 and is removed from drupal:9.0.0. Use Drupal::entityTypeManager() instead in most cases. If the needed method is not on \Drupal\Core\Entity\EntityTypeManagerInterface, see the deprecated \Drupal\Core\Entity\EntityManager to find the correct interface or service.
Add core_version_requirement: ^8 || ^9 to designate that the module is compatible with Drupal 9. See https://drupal.org/node/3070687.
Routes.php uses a deprecated and removed function:
Call to deprecated method entityManager() of class Drupal. Deprecated in drupal:8.0.0 and is removed from drupal:9.0.0. Use Drupal::entityTypeManager() instead in most cases. If the needed method is not on \Drupal\Core\Entity\EntityTypeManagerInterface, see the deprecated \Drupal\Core\Entity\EntityManager to find the correct interface or service.
Add core_version_requirement: ^8 || ^9 to designate that the module is compatible with Drupal 9. See https://drupal.org/node/3070687.