Issue #3518383: Update core_version_requirement for Drupal 11 compatibility

Update core_version_requirement for Drupal 11 compatibility

To test:

1. Git clone this repo into your local. Put it somewhere that you can easily remember.

2. Go to your working space in your local machine and spin up a vanilla Drupal 11 site.

3. Copy the cloned folder of this repo and place it under /modules/contrib in your vanilla Drupal 11.

4. In your Drupal 11 site, enable the module.

5. Add the plugin to the Basic HTML and other editor types in your admin/config/content/formats

6. Hit save. No errors should be happening and everything should save well after adding the button to your toolbar in your chosen editor type.

7. Create a new piece of content. Like an article or basic page.

8. Use the plugin. See the below steps:

9. In your cke. Click the citation button in the cke toolbar. Start typing. You will see your text appear in a citation tag and therefore visually in the wysiwyg you will see your text is slanted like it was italicized, but its not, it is cited. See image below:

2. Click the citation button again. And start typing. You will now see your text appear as normal. It is now outside of your citation tag.

3. Now highlight the normal text you just wrote. Click the citation button and see your text appear slanted. The cite tags (both opening and closing) have now been added to your text.

4. Highlight your first text at the beginning that you wrote in the first step. Now click on the citation button again and watch as the text appears normal as the citation tags surrounding it are removed.

5. Each time you add a citation in your text, check the Source and see the cite tag is there.
6. When you hit Save and create your content make sure the cite tags that you added are working when you view your content.