Remove Stripe config settings

These now ship with a dedicated config file for Cashier.

config/services.php

@@ -8,7 +8,7 @@ return [
     |--------------------------------------------------------------------------
     |
     | This file is for storing the credentials for third party services such
-    | as Stripe, Mailgun, SparkPost and others. This file provides a sane
+    | as Mailgun, SparkPost and others. This file provides a sane
     | default location for this type of information, allowing packages
     | to have a conventional place to find your various credentials.
     |
@@ -34,14 +34,4 @@ return [
         'secret' => env('SPARKPOST_SECRET'),
     ],
 
-    'stripe' => [
-        'model' => App\User::class,
-        'key' => env('STRIPE_KEY'),
-        'secret' => env('STRIPE_SECRET'),
-        'webhook' => [
-            'secret' => env('STRIPE_WEBHOOK_SECRET'),
-            'tolerance' => env('STRIPE_WEBHOOK_TOLERANCE', 300),
-        ],
-    ],
-
 ];