Changes: Added changes for root tag improvements in IECoreUSD

Author: lucienfostier

Changes

@@ -48,10 +48,23 @@ Breaking Changes
 - Removed support for `IECORE_RTLD_GLOBAL` environment variable.
 - SmoothSkinningData : Removed, along with all associated Ops and Parameters.
 
-10.5.x.x (relative to 10.5.15.3)
+10.5.x.x (relative to 10.5.15.4)
+=======
+
+
+
+10.5.15.4 (relative to 10.5.15.3)
 ========
 
+Improvements
+-----
+
+- IECoreUSD: Added support for root level tags (reading/writing) to our IECoreUSD::SceneCacheData plugin.
+
+Fixes
+-----
 
+- IECoreUSD: Fixed crash when using invalid file path with IECoreUSD::SceneCacheFileFormat.
 
 10.5.15.3 (relative to 10.5.15.2)
 =========