Declare Drupal 10 support

composer.json

@@ -34,7 +34,7 @@
         }
     ],
     "require": {
-        "drupal/core": "^9"
+        "drupal/core": "^9 || ^10"
     },
     "require-dev": {
         "drupal/coder": "^8.3",

jsonapi_image_styles.info.yml

 name: 'JSON:API Image Styles'
 type: module
 description: 'Expose image styles to JSON:API'
-core_version_requirement: ^9
+core_version_requirement: ^9 || ^10
 package: 'Web services'
 dependencies:
   - drupal:jsonapi

tests/src/Functional/JsonApiImageStylesFunctionalTestBase.php

@@ -21,7 +21,7 @@ abstract class JsonApiImageStylesFunctionalTestBase extends JsonApiFunctionalTes
   /**
    * {@inheritdoc}
    */
-  protected function setUp() {
+  protected function setUp(): void {
     parent::setUp();
     $config = \Drupal::configFactory()->getEditable('jsonapi_image_styles.settings');
     $config->set('image_styles', [