How change the allowed values of a select list or radio field dynamically in drupal 8

field.storage.node.field_name.yml

settings:
  allowed_values: {  }
  # Add the line below to your file as it will reference the function you'll create in your .module file
  allowed_values_function: example_allowed_values_function

module_name.module

use Drupal\Core\Entity\ContentEntityInterface;
use Drupal\field\Entity\FieldStorageConfig;

/**
 * Set dynamic allowed values for the content author field(s).
 *
 * @param \Drupal\field\Entity\FieldStorageConfig $definition
 *   The field definition.
 * @param \Drupal\Core\Entity\ContentEntityInterface|null $entity
 *   The entity being created if applicable.
 * @param bool $cacheable
 *   Boolean indicating if the results are cacheable.
 *
 * @return array
 *   An array of possible key and value options.
 *
 * @see options_allowed_values()
 */
function example_allowed_values_function(FieldStorageConfig $definition, ContentEntityInterface $entity = NULL, $cacheable) {
  $options = [
    'current_user' => 'Current user',
    'content_creator' => 'Content user'
  ];
  return $options;
}

Some notes:

1. once the field storage file is updated you will need to run drush cim for the changes to come into effect
2. this code is based on the following article you should read it for further detail: https://chromatichq.com/blog/dynamic-default-and-allowed-values-list-fields-drupal-8