Class "Pelago\Emogrifier" not found

Problem/Motivation

I am getting the following error when submitting the configuration form:
Error: Class "Pelago\Emogrifier" not found in Drupal\pdf_html\Form\PdfHtmlForm->processItem() (line 360 of /var/www/html/web/modules/contrib/pdf_html/src/Form/PdfHtmlForm.php)

It seems the implementation of emogrifier here has changed: https://github.com/MyIntervals/emogrifier#migrating-from-the-dropped-emo...

I have added a patch to fix the issue.