Add release notes for 1.3.15 (#5999) (#6019)

(cherry picked from commit 1da1320)

Signed-off-by: abbyhu2000 <abigailhu2000@gmail.com>
Signed-off-by: github-actions[bot] <github-actions[bot]@users.noreply.github.com>
Co-authored-by: github-actions[bot] <github-actions[bot]@users.noreply.github.com>

release-notes/opensearch-dashboards.release-notes-1.3.15.md

@@ -0,0 +1,20 @@
+# Version 1.3.14 Release Notes
+
+### 🛡 Security
+
+### 📈 Features/Enhancements
+
+### 🐛 Bug Fixes
+
+- [OSCI][fix] Discover: Fix the Subfields Display Issue ([#5429](https://github.com/opensearch-project/OpenSearch-Dashboards/pull/5429))
+- [BUG][data] Support for custom filters with heterogeneous data fields ([#5577](https://github.com/opensearch-project/OpenSearch-Dashboards/pull/5577))
+
+### 🚞 Infrastructure
+
+### 📝 Documentation
+
+### 🛠 Maintenance
+
+- [Version] Increment version to 1.3.15 ([#5596](https://github.com/opensearch-project/OpenSearch-Dashboards/pull/5596))
+- Add @SuZhou-Joe as a maintainer. ([#5594](https://github.com/opensearch-project/OpenSearch-Dashboards/pull/5594))
+- Move @seanneumann to emeritus maintainer ([#5634](https://github.com/opensearch-project/OpenSearch-Dashboards/pull/5634))