chore: migrate to eslint v9 (yeoman#559)

Author: mshima

.eslintignore

@@ -0,0 +1,21 @@
+// @ts-check
+import configs from '@yeoman/eslint';
+import { config } from 'typescript-eslint';
+
+export default config(
+  ...configs,
+  { ignores: ['test/fixtures/'] },
+  {
+    rules: {
+      '@typescript-eslint/no-this-alias': 'off',
+      'no-undef': 'off',
+      'prefer-destructuring': 'off',
+      'unicorn/no-array-for-each': 'off',
+      'unicorn/no-array-push-push': 'off',
+      'unicorn/no-array-reduce': 'off',
+      'unicorn/no-this-assignment': 'off',
+      'unicorn/prefer-spread': 'off',
+      'unicorn/prevent-abbreviations': 'off',
+    },
+  },
+);