chore: update node to 22 and update readme for eslint.config.js (#122)

Author: ben-zhang-at-salesforce

README.md

@@ -22,6 +22,21 @@ $ npm install --save-dev @salesforce/eslint-plugin-lwc-mobile
 
 The default configurations are now in the flat config format supported by ESLint 9 and beyond. To include `recommendedConfigs ` in your flat config, spread it into your configuration array. Note that `recommendedConfigs` is a collection of preset configs and must be expanded accordingly.:
 
+```javascript
+// eslint.config.js
+const { defineConfig } = require("eslint/config");
+const lwcMobilePlugin = require("@salesforce/eslint-plugin-lwc-mobile");
+
+module.exports = defineConfig([
+    {
+        plugins: {
+            "@salesforce/lwc-mobile": lwcMobilePlugin,
+        },
+        extends: [...lwcMobilePlugin.recommendedConfigs],
+    },
+]);
+```
+
 ```javascript
 // eslint.config.mjs
 import js from '@eslint/js';

package-lock.json

@@ -51,7 +51,10 @@
         "trailingComma": "none"
     },
     "engines": {
-        "node": ">=20"
+        "node": ">=22"
+    },
+    "volta": {
+        "node": "22.21.1"
     },
     "type": "commonjs",
     "main": "dist/index.js",
@@ -96,9 +99,6 @@
     "peerDependencies": {
         "eslint": ">=7"
     },
-    "volta": {
-        "node": "20.18.0"
-    },
     "publishConfig": {
         "registry": "https://registry.npmjs.org/"
     }