Update CHANGELOG.md with Release Date (#37486)

Author: needuv

sdk/evaluation/azure-ai-evaluation/CHANGELOG.md

@@ -1,6 +1,6 @@
 # Release History
 
-## 1.0.0b1 (Unreleased)
+## 1.0.0b1 (2024-20-09)
 
 ### Breaking Changes
 
@@ -10,7 +10,6 @@
 - Model configurations classes are now of type `TypedDict` and are exposed in the `azure.ai.evaluation` module instead of coming from `promptflow.core`.  
 - Updated the parameter names for `question` and `answer` in built-in evaluators to more generic terms: `query` and `response`.
 
-
 ### Features Added
 
 - First preview