refactor(cache): set native type for $value in DummyHandler::save() method

Author: yassinedoghri

system/Cache/Handlers/DummyHandler.php

@@ -36,10 +36,7 @@ public function remember(string $key, int $ttl, Closure $callback): mixed
         return null;
     }
 
-    /**
-     * @param mixed $value
-     */
-    public function save(string $key, $value, int $ttl = 60): bool
+    public function save(string $key, mixed $value, int $ttl = 60): bool
     {
         return true;
     }