[Discord] changed to the new cdn path (#20)

ムjakeム - Jan 8th, 2017
@shylor we don't use discordcdn.com anymore.

Provider.php

@@ -69,7 +69,7 @@ protected function mapUserToObject(array $user)
             'nickname' => sprintf('%s#%d', $user['username'], $user['discriminator']),
             'name' => $user['username'],
             'email' => $user['email'],
-            'avatar' => (is_null($user['avatar'])) ? null : sprintf('https://discordcdn.com/avatars/%s/%s.jpg', $user['id'], $user['avatar']),
+            'avatar' => (is_null($user['avatar'])) ? null : sprintf('https://cdn.discordapp.com/avatars/%s/%s.jpg', $user['id'], $user['avatar']),
         ]);
     }