Use HandlerStack::create() in Guzzle tracing middleware snippet (#13033)

Author: raccube

docs/platforms/php/common/tracing/instrumentation/requests-module.mdx

@@ -18,7 +18,7 @@ For detailed information about which data can be set, see the [Requests Module d
 If you're using [Guzzle](https://github.com/guzzle/guzzle), you can inject Sentry's `GuzzleTracingMiddleware` into your `HandlerStack`.
 
 ```php
-$stack = new \GuzzleHttp\HandlerStack();
+$stack = \GuzzleHttp\HandlerStack::create();
 $stack->setHandler(new \GuzzleHttp\Handler\CurlHandler());
 $stack->push(\Sentry\Tracing\GuzzleTracingMiddleware::trace());