Add release notes for 3.5.0

Signed-off-by: opensearch-ci <opensearch-infra@amazon.com>

Author: opensearch-ci-bot

release-notes/opensearch-observability.release-notes-3.5.0.0.md

@@ -3,5 +3,6 @@
 Compatible with OpenSearch and OpenSearch Dashboards version 3.5.0
 
 ### Maintenance
+
 * Upgrade to ktlint-cli 1.8.0 ([#1962](https://github.com/opensearch-project/observability/pull/1962))
 * Decouple jackson annotation version ([#1968](https://github.com/opensearch-project/observability/pull/1968))