Update LaravelHttpClientLoggerServiceProvider.php

Explicitly mark parameter $logger as nullable

The parameter has a default value of null, but isn't explicitly 
marked as nullable, which causes a warning in PHP 8.4

Author: dpash

src/LaravelHttpClientLoggerServiceProvider.php

@@ -59,7 +59,7 @@ public function packageBooted()
             }
         });
 
-        PendingRequest::macro('logWith', function (HttpLoggerInterface $logger = null): PendingRequest {
+        PendingRequest::macro('logWith', function (?HttpLoggerInterface $logger = null): PendingRequest {
             /** @var \Illuminate\Http\Client\PendingRequest $this */
             return $this->withMiddleware((new LoggingMiddleware($logger, new LogAllFilter()))->__invoke());
         });