[BC Break] Disable namespace in default FilesystemAdapter, you can control this by the cache_directory option already

Author: Toflar

src/Psr6Store.php

@@ -119,7 +119,7 @@ public function __construct(array $options = [])
             }
 
             return new TagAwareAdapter(
-                new FilesystemAdapter('http_cache', 0, $options['cache_directory'])
+                new FilesystemAdapter('', 0, $options['cache_directory'])
             );
         })->setAllowedTypes('cache', AdapterInterface::class);