Documentation update on CKEditor dependencies

Hi,

I think it's worth to update module description, as looking at https://www.drupal.org/project/ckeditor_config → - it is very uncler if module can be used with core CKEditor or if it works with CKE 5 or only CKE 4.

Warning at the begining, about the dependency on contrib module says: Composer-related issues caused by this change in Drupal.org's infrastructure are addressed in the 8.x-3.2 release. But it doesn;t answer the question if dependency is removes or it's still there after 8.x-3.2. Also, readme.md still mentions dependency on core CKEditor module, while composer actually has dependency on contrib.

Can this be added to the module page? And can readme.md be updated?