chore: Fix release notes config

We need to ignore backport related PRs from release notes
as they will end up in the patch level releases of the stable
branches.

Author: tvdeyen

.github/release.yml

@@ -6,6 +6,10 @@ changelog:
     labels:
       - skip-changelog
       - chore
+      - backport-to-8.0-stable
+      - backport-to-8.1-stable
+      - backport-to-8.2-stable
+      - backport-to-8.3-stable
 
   categories:
     - title: "Breaking Changes"