Switch custom Guzzle integration for Laravel's HTTP facade

Commit also adds config options to the example file.

.env.example

@@ -13,6 +13,11 @@ DB_DATABASE=laravel
 DB_USERNAME=root
 DB_PASSWORD=
 
+RECAPTCHA_SITE_KEY=
+RECAPTCHA_PRIVATE_KEY=
+RECAPTCHA_VERIFY_URL="https://www.google.com/recaptcha/api/siteverify"
+# WARNING: Your contact form will be useless if you change this value. Only change this URL if Google updates it.
+
 BROADCAST_DRIVER=log
 CACHE_DRIVER=file
 QUEUE_CONNECTION=sync

app/Http/Controllers/ContactController.php

@@ -4,15 +4,13 @@ namespace App\Http\Controllers;
 
 use Illuminate\Http\Request;
 use GuzzleHttp;
+use Illuminate\Support\Facades\Http;
 
 class ContactController extends Controller
 {
 
     public function create(Request $request)
     {
-        // TODO: use service provider instead
-        $client = new GuzzleHttp\Client();
-
         $name = $request->name;
         $email = $request->email;
         $subject = $request->subject;
@@ -20,13 +18,12 @@ class ContactController extends Controller
 
         $challenge = $request->input('captcha');
 
-        $verifyrequest = $client->request('POST', config('recaptcha.verify.apiurl'), [
-            'form_params' => [
+        $verifyrequest = Http::asForm()->post(config('recaptcha.verify.apiurl'), [
             'secret' => config('recaptcha.keys.secret'),
             'response' => $challenge,
             'remoteip' => $_SERVER['REMOTE_ADDR']
-            ]
         ]);
+
         $response = json_decode($verifyrequest->getBody(), true);
 
         if (!$response['success'])