update changenote

Author: petschki

CHANGES.rst

@@ -4,17 +4,12 @@ Changelog
 6.2.8 (unreleased)
 ------------------
 
-Breaking changes:
-
-- *add item here*
-
 New features:
 
 - Fix SCSS imports for latest Bootstrap 5.3.
-
-Bug fixes:
-
-- *add item here*
+  See `Upgrade notes <https://github.com/plone/bobtemplates.plone/blob/main/docs/templates/addon/theme_barceloneta/index.rst#upgrade-notes>`_
+  how you can update your existing theme.
+  [petschki]
 
 
 6.2.7 (2023-06-19)