[BUG] PhpImap is not compatible with PHP8.4

[genyslt]

Environment (please complete the following information):

• PHP IMAP version: 5.0.1
• PHP Version: 8.4.5

Describe the bug PhpImap\Mailbox::__construct(): Implicitly marking parameter $attachmentsDir as nullable is deprecated, the explicit nullable type must be used instead

To Reproduce PHPSTAN

The used code:

$mailbox =  new Mailbox(
			$connection_strin,
			$username,
			$password,
			$attachmentsDir
		);

PhpImap\Mailbox::__construct(): Implicitly marking parameter $attachmentsDir as nullable is deprecated, the explicit nullable type must be used instead