Upgrade eslint to v9.

.github/dependabot.yml

@@ -13,10 +13,6 @@ updates:
     labels:
       - 'dependencies'
     groups:
-      typescript-eslint:
-        patterns:
-          - '@typescript-eslint/eslint-plugin'
-          - '@typescript-eslint/parser'
       comet-uswds:
         patterns:
           - '@metrostar/comet-uswds'

eslint.config.js

@@ -0,0 +1,31 @@
+import pluginJs from '@eslint/js';
+import reactPlugin from 'eslint-plugin-react';
+import tseslint from 'typescript-eslint';
+
+export default [
+  {
+    files: ['**/*.{js,mjs,cjs,ts,jsx,tsx}'],
+    settings: {
+      react: {
+        version: 'detect',
+      },
+    },
+    languageOptions: {
+      parserOptions: {
+        ecmaFeatures: {
+          jsx: true,
+        },
+      },
+    },
+  },
+  pluginJs.configs.recommended,
+  ...tseslint.configs.recommended,
+  reactPlugin.configs.flat.recommended,
+  {
+    rules: {
+      '@typescript-eslint/no-unsafe-function-type': 'off',
+      '@typescript-eslint/no-unused-expressions': 'off',
+      'react/react-in-jsx-scope': 'off',
+    },
+  },
+];