Finalize changelog for v1.38.3

Author: jstone-lucasfilm

CHANGELOG.md

@@ -1,9 +1,9 @@
 # Change Log
 
-## [1.38.3] - Development
+## [1.38.3] - 2021-12-14
 
 ### Added
-- Added NodeDef inheritance for Autodesk Standard Surface versions 1.0.0 and 1.0.1.
+- Added inheritance structure for Autodesk Standard Surface versions 1.0.0 and 1.0.1.
 - Added versioning and customization support to MaterialX namespaces in C++.
 - Added preprocessor definitions for the API version to MaterialXCore.
 - Added color transform methods to the Image class.