Update CHANGELOG

Author: stellasia

CHANGELOG.md

@@ -7,6 +7,11 @@
 - Added the `run_with_context` method to `Component`. This method includes a `context_` parameter, which provides information about the pipeline from which the component is executed (e.g., the `run_id`). It also enables the component to send events to the pipeline's callback function.
 
 
+### Changed
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+- Improved log output readability in Retrievers and GraphRAG and added embedded vector to retriever result metadata for debugging.
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 ## 1.6.0
 
 ### Added