fix(ci): release description file ref

.gitlab-ci.yml

@@ -72,6 +72,6 @@ release_job:
     - echo "this will be a release when there is a tag, but tags should be protected to be only createable by maintainers."
   release:
     name: 'Release $CI_COMMIT_TAG'
-    description: ./CHANGELOG
+    description: ./CHANGELOG.md
     tag_name: '$CI_COMMIT_TAG'
     ref: '$CI_COMMIT_TAG'