Drupal 10 compatibility fixes

I have created this patch to make this module Drupal 10 compatible.
Please review this patch.

Applied and tested patch #2 in Drupal 9.5.7 and 10.0.8. Patch applied cleanly and makes this module D10 compatible. Functionality is working fine.

Moving this to RTBC.

In order this patch works we have to update the mpdf/mpdf library to ^8.0.0 to work with php ^8.0.
When we try to run composer require it breaks because the library is set to ^7.0.0 that requires php ^7.0.0.

Patch for 2.x-dev which allows ^8.0.4

See note in ✨ PDF using mPDF D10 compatibility? Needs work about how to make D10 compatible along with mpdf dependency

I encountered issues with Drupal Version 9.5.11. The module version that I was able to patch is as follows:

name: PDF using mPDF
type: module
description: 'HTML to PDF conversion using mPDF Library'
core: 8.x 
core_version_requirement: ^8 || ^9
package: 'PDF Conversion'
configure: pdf_using_mpdf.admin_form

Details on the errors I had to address, please refer to this screenshot: Link to Screenshot →

I successfully resolved the issues with the following patch: Patch Link. →

The patch https://www.drupal.org/files/issues/2023-10-17/pdf_using_mpdf_d10_compac... → works perfectly. Thank you.

Call to deprecated function render(): in drupal:9.3.0 and is removed from drupal:10.0.0. Use \Drupal\Core\Render\RendererInterface::render() instead.

/src/Controller/GeneratePdf.php

- $renderedNode = render($view)->__toString();
+ $renderedNode = \Drupal::service('renderer')->render($view)->__toString();