Update changelog for 1.15 release (#1433)

Signed-off-by: Viraj Sanghvi <[email protected]>

CHANGELOG.md

@@ -1,14 +1,11 @@
 # OUI
 
-## [Unreleased `1.x`](https://github.com/opensearch-project/oui/tree/1.x)
+## [`1.15.0`](https://github.com/opensearch-project/oui/tree/1.15)
 
 ### Deprecations
 
 - Deprecate Query.toESQuery and Query.toESQueryString in favor of Query.toOpenSearchQuery and Query.toOpenSearchQueryString ([#1426](https://github.com/opensearch-project/oui/pull/1426))
 
-### 🛡 Security
-
-
 ### 📈 Features/Enhancements
 
 - Reduce the gap between the elements of a compressed OuiSearchBar ([#1426](https://github.com/opensearch-project/oui/pull/1426))
@@ -19,20 +16,6 @@
 - Fix naming conventions in OuiSearchBar code and docs ([#1426](https://github.com/opensearch-project/oui/pull/1426))
 - Revert button background color configurability ([#1430](https://github.com/opensearch-project/oui/pull/1430)) 
 
-### 🚞 Infrastructure
-
-
-### 📝 Documentation
-
-
-### 🛠 Maintenance
-
-
-### 🪛 Refactoring
-
-
-### 🔩 Tests
-
 
 ## [`1.14.0`](https://github.com/opensearch-project/oui/tree/1.14)