Deprecated function. Can we update dependancies?

Problem/Motivation

Drupal Log is throwing deprecation warning;
Message Deprecated function: Creation of dynamic property OpenPGP_SignaturePacket_Subpacket::$length is deprecated in OpenPGP_SignaturePacket::get_subpacket() (line 881 of /app/vendor/singpolyma/openpgp-php/lib/openpgp.php)

Steps to reproduce

Use the Drupal\openpgp_encryption\Plugin\EncryptionMethod\OpenPGP->encrypt() method in a custom module.

Proposed resolution

Update singpolyma/openpgp-php 0.3.0 to version 0.7.0 -> https://packagist.org/packages/singpolyma/openpgp-php
Version 0.6.0 in composer does not have this updated either (https://github.com/singpolyma/openpgp-php/commit/f4dbc2f370b3d4eaa7e0cf8...)

Remaining tasks

User interface changes

API changes

Data model changes