Add todo to remove code when drupal 8 support is dropped

src/ResourceType/ConfigurableResourceTypeRepository.php

@@ -300,6 +300,8 @@ class ConfigurableResourceTypeRepository extends ResourceTypeRepository {
 
   /**
    * {@inheritdoc}
+   *
+   * @todo Remove this code when Drupal 8 support is dropped
    */
   protected function getRelatableResourceTypesFromFieldDefinition(FieldDefinitionInterface $field_definition, array $resource_types) {
     $item_definition = $field_definition->getItemDefinition();
@@ -338,6 +340,8 @@ class ConfigurableResourceTypeRepository extends ResourceTypeRepository {
 
   /**
    * {@inheritdoc}
+   *
+   * @todo Remove this code when Drupal 8 support is dropped
    */
   protected function getAllBundlesForEntityType($entity_type_id) {
     // Ensure all keys are strings, because numeric values are allowed
@@ -357,6 +361,8 @@ class ConfigurableResourceTypeRepository extends ResourceTypeRepository {
    *
    * @return \Drupal\jsonapi\ResourceType\ResourceType|null
    *   The resource type or NULL if it cannot be found.
+   *
+   * @todo Remove this code when Drupal 8 support is dropped
    */
   protected static function lookupResourceType(array $resource_types, $entity_type_id, $bundle) {
     if (isset($resource_types["$entity_type_id--$bundle"])) {