Update dependency eslint to v9 (#230)

* Update dependency eslint to v9

* use new config format

---------

Co-authored-by: renovate[bot] <29139614+renovate[bot]@users.noreply.github.com>
Co-authored-by: Jonathan Gray <jonmattgray@gmail.com>

eslint.config.mjs

@@ -0,0 +1,39 @@
+import typescriptEslint from '@typescript-eslint/eslint-plugin'
+import prettier from 'eslint-plugin-prettier'
+import tsParser from '@typescript-eslint/parser'
+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: __dirname,
+  recommendedConfig: js.configs.recommended,
+  allConfig: js.configs.all,
+})
+
+export default [
+  {
+    ignores: ['**/node_modules', '**/lib', '**/build'],
+  },
+  ...compat.extends(
+    'eslint:recommended',
+    'plugin:@typescript-eslint/eslint-recommended',
+    'plugin:@typescript-eslint/recommended',
+    'prettier'
+  ),
+  {
+    plugins: {
+      '@typescript-eslint': typescriptEslint,
+      prettier,
+    },
+
+    languageOptions: {
+      parser: tsParser,
+    },
+
+    files: ['**/*.ts'],
+  },
+]