release: cut CHANGELOG for 5.0.3 (#281)

Author: unknwon

charts/sourcegraph/CHANGELOG.md

@@ -8,6 +8,8 @@ Use `**BREAKING**:` to denote a breaking change
 
 ## Unreleased
 
+## 5.0.3
+
 - Add Embeddings service (disabled by default) for Cody embeddings
 
 ## 5.0.1