chore: move to ESM based eslint config

Author: basti1302

eslint.config.js renamed to eslint.config.mjs

@@ -1,23 +1,19 @@
 // SPDX-FileCopyrightText: Copyright 2024 Dash0 Inc.
 // SPDX-License-Identifier: Apache-2.0
 
-/* global module, require */
-/* eslint-disable @typescript-eslint/no-require-imports */
+// @ts-check
 
-'use strict';
+import eslint from '@eslint/js';
+import tseslint from 'typescript-eslint';
 
-const eslint = require('@eslint/js');
-const tsEsLint = require('typescript-eslint');
+import header from 'eslint-plugin-header';
+import mocha from 'eslint-plugin-mocha';
+import simpleImportSort from 'eslint-plugin-simple-import-sort';
+import unusedImports from 'eslint-plugin-unused-imports';
 
-const header = require('eslint-plugin-header');
-const mocha = require('eslint-plugin-mocha');
-const simpleImportSort = require('eslint-plugin-simple-import-sort');
-const unusedImports = require('eslint-plugin-unused-imports');
-
-module.exports = tsEsLint.config(
-  //
+export default tseslint.config(
   eslint.configs.recommended,
-  ...tsEsLint.configs.recommended,
+  tseslint.configs.recommended,
   {
     plugins: {
       header,

package.json

@@ -8,10 +8,10 @@
     "build": "rimraf dist && tsc --build --force",
     "verify": "npm run lint && npm test",
     "lint": "npm run eslint && npm run prettier-check",
-    "eslint": "eslint eslint.config.js src test",
+    "eslint": "eslint eslint.config.mjs src test",
     "prepack": "rimraf dash0hq-opentelemetry-*.tgz && npm run build",
-    "prettier": "prettier --write eslint.config.js .mocharc.js 'src/**/*.[jt]s' 'test/**/*.[jt]s' --parser typescript",
-    "prettier-check": "prettier --check eslint.config.js 'src/**/*.[jt]s' 'test/**/*.[jt]s' --parser typescript",
+    "prettier": "prettier --write eslint.config.mjs .mocharc.js 'src/**/*.[jt]s' 'test/**/*.[jt]s' --parser typescript",
+    "prettier-check": "prettier --check eslint.config.mjs 'src/**/*.[jt]s' 'test/**/*.[jt]s' --parser typescript",
     "test": "npm run test:unit && npm run test:integration",
     "test:unit": "mocha --config test/.mocharc.unit.js --require ts-node/register",
     "test:integration": "npm run test:integration:default && npm run test:integration:minimum-version-check",