SWED-2275 release-notes

RELEASE_NOTES.md

@@ -5,6 +5,8 @@
 ## Component changes
 
 - Cards
+  - new Cards UI. To migrate requires code changes from DG consuming devs. BUT silent support for "old" card syntax. Please check the documentation for more details.
+  - the new UI requires the introduction of new classes (.cards-cta, span.arrow, ...). Unless one of these new classes (`.cards-cta`) is present, then the old UI will be used, by checking conditionally `cards:has(.cards-cta)`. If your project does NOT support the :has() selector yet, but requires fallback support for the old UI, then add `.legacy` class to the `.cards` element.
 
 ## Technical changes