docs: Update OAUTH documentation to reflect a deprecation of a method (#2683)

Author: Hectorhammett

docs/oauth-web.md

@@ -353,7 +353,7 @@ require_once __DIR__.'/vendor/autoload.php';
 session_start();
 
 $client = new Google\Client();
-$client->setAuthConfigFile('client_secrets.json');
+$client->setAuthConfig('client_secrets.json');
 $client->setRedirectUri('http://' . $_SERVER['HTTP_HOST'] . '/oauth2callback.php');
 $client->addScope(Google\Service\Drive::DRIVE_METADATA_READONLY);
 
@@ -421,4 +421,4 @@ $client->revokeToken();
 
 **Note:** Following a successful revocation response, it might take some time before the revocation has full effect.
 
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+Except as otherwise noted, the content of this page is licensed under the [Creative Commons Attribution 4.0 License](https://creativecommons.org/licenses/by/4.0/), and code samples are licensed under the [Apache 2.0 License](https://www.apache.org/licenses/LICENSE-2.0). For details, see our [Site Policies](https://developers.google.com/terms/site-policies). Java is a registered trademark of Oracle and/or its affiliates.