build: fix eslint.config following esm update (eslint-community#527)

This change updates the eslint config to use `sourceType: 'module'`, and swaps n's `flat/mixed-esm-and-cjs` config for `flat/recommended` which will use the module type from the nearest `package.json`.

Author: michaelfaith

eslint.config.js

@@ -13,13 +13,21 @@ const compat = new FlatCompat({
 });
 
 export default [
+  // Global ignores
+  {
+    ignores: ['node_modules', 'coverage'],
+  },
+  // Global settings
+  {
+    languageOptions: { sourceType: 'module' },
+  },
   ...compat.extends(
     'not-an-aardvark/node',
     'plugin:@eslint-community/eslint-comments/recommended',
     'plugin:prettier/recommended',
     'plugin:unicorn/recommended',
   ),
-  ...pluginN.configs['flat/mixed-esm-and-cjs'],
+  pluginN.configs['flat/recommended'],
   {
     rules: {
       '@eslint-community/eslint-comments/no-unused-disable': 'error',
@@ -52,10 +60,6 @@ export default [
       ],
     },
   },
-  {
-    files: ['tests/**/*.js'],
-    languageOptions: { sourceType: 'module' },
-  },
   {
     files: ['**/*.md'],
     plugins: { markdown },