Update testing matrix and add forgotten drupal core compatibility.

[rosiel]

GitHub Issue: Islandora/documentation#2324

• Other Relevant Links (Google Groups discussion, related pull requests,
  Release pull requests, etc.)
• Add SVG icons to field types. #126 added the drupal 10.2 field category API, but didn't properly change the drupal core compatibility status.

What does this Pull Request do?

Updates us to drop 10.1 and test on 10.4.x-dev.

What's new?

• Testing matrix

• drupal core compatibility

• Does this change require documentation to be updated? no

• Does this change add any new dependencies? no

• Does this change require any other modifications to be made to the repository
  (i.e. Regeneration activity, etc.)? no

• Could this change impact execution of existing code? no

How should this be tested?

A description of what steps someone could take to:

• Reproduce the problem you are fixing (if applicable)
• Test that the Pull Request does what is intended.
• Please be as detailed as possible.
• Good testing instructions help get your PR completed faster.

Additional Notes:

Any additional information that you think would be helpful when reviewing this
PR.

Interested parties

Tag (@ mention) interested parties or, if unsure, @Islandora/committers