Drupal 11 compatible version

Problem/Motivation

We need to be able to use this widget on a Drupal 11 web site.

Proposed resolution

- Update the two modules info.yml files.
- Update the PHPUnit JavaScript tests.
- GitLabCI fixes.

Remaining tasks

Validate MR.

Testing on Drupal 11

To test on Drupal 11, add the following lines to your composer.json repositories section:

  "repositories": [
    {
      "type": "vcs",
      "url": "https://git.drupalcode.org/issue/readonly_field_widget-3475883.git"
    },

and then run:

composer require drupal/readonly_field_widget:dev-3475883-drupal-11-compatible