Only get changelog for core commits (#27900)

dev/airflow-github

@@ -300,7 +300,10 @@ def changelog(previous_version, target_version, github_token):
         if tickets:
             issue = gh_repo.get_issue(number=int(tickets[0][1:]))
             issue_type = get_issue_type(issue)
-            sections[issue_type].append(commit["subject"])
+            files = files_touched(repo, commit["id"])
+            if is_core_commit(files):
+                sections[issue_type].append(commit["subject"])
+
         else:
             sections[DEFAULT_SECTION_NAME].append(commit["subject"])