Update mergegate to exclude dd-octo-sts

Author: iunanua

repository.datadog.yml

@@ -13,4 +13,4 @@ rules:
   - require: all-files-are-owned
   - require: commit-signatures
     excluded_emails:
-      - '41898282+github-actions[bot]@users.noreply.github.com' # version-bump bots
+      - '200755185+dd-octo-sts[bot]@users.noreply.github.com' # version-bump bots