Use @eslint/migrate-config-generated ESLint config

This change has no real impact and is only for aesthetic consistency
across our ESLint projects.

eslint.config.js → eslint.config.mjs

@@ -2,11 +2,15 @@
 //
 // SPDX-License-Identifier: AGPL-3.0-only
 
+import path from "node:path";
+import { fileURLToPath } from "node:url";
 import js from "@eslint/js";
 import { FlatCompat } from "@eslint/eslintrc";
 
+const __filename = fileURLToPath(import.meta.url);
+const __dirname = path.dirname(__filename);
 const compat = new FlatCompat({
-    baseDirectory: import.meta.dirname,
+    baseDirectory: __dirname,
     recommendedConfig: js.configs.recommended,
     allConfig: js.configs.all
 });
@@ -56,4 +60,4 @@ export default [{
 })), {
     files: ["**/*.html"],
     rules: {},
-}];
+}];