chore(ci): fix changelog update on PRs merged in release branches (#2244)

Signed-off-by: Maksim Fedotov <maksim.fedotov@flant.com>

Author: nevermarine

.github/workflows/changelog-by-pull.yml

@@ -20,6 +20,7 @@ on:
       - "edited"
     branches:
       - "main"
+      - "release-[0-9]+.[0-9]+"
 jobs:
   changelog:
     # Conditions: