docs: Add link to changelog

Signed-off-by: Mike McKiernan <[email protected]>

Author: mikemckiernan

docs/release-notes.md

@@ -8,6 +8,10 @@ tocdepth: 2
 
 # Release Notes
 
+The following sections summarize and highlight the changes for each release.
+For a complete record of changes in a release, refer to the
+[CHANGELOG.md](https://github.com/NVIDIA/NeMo-Guardrails/blob/develop/CHANGELOG.md) in the GitHub repository.
+
 ## 0.14.0
 
 ### Breaking Changes