build: Update ESLint to v9 (#16639)

packages/@n8n/backend-test-utils/.eslintrc.js

@@ -1,7 +0,0 @@
-const sharedOptions = require('@n8n/eslint-config/shared');
-
-/** @type {import('@types/eslint').ESLint.ConfigData} */
-module.exports = {
-	extends: ['@n8n/eslint-config/base'],
-	...sharedOptions(__dirname),
-};

packages/@n8n/backend-test-utils/eslint.config.mjs

@@ -0,0 +1,10 @@
+import { defineConfig } from 'eslint/config';
+import { baseConfig } from '@n8n/eslint-config/base';
+
+export default defineConfig(baseConfig, {
+	rules: {
+		// TODO: Remove this
+		'@typescript-eslint/require-await': 'warn',
+		'@typescript-eslint/naming-convention': 'warn',
+	},
+});

packages/@n8n/backend-test-utils/package.json

@@ -8,7 +8,7 @@
     "build": "tsc -p tsconfig.build.json",
     "format": "biome format --write .",
     "format:check": "biome ci .",
-    "lint": "eslint .",
+    "lint": "eslint . --quiet",
     "lintfix": "eslint . --fix",
     "watch": "tsc -p tsconfig.build.json --watch",
     "test": "jest",