[ai-content-safety] Update release date in CHANGELOG (Azure#27194)

### Packages impacted by this PR


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there are more than one possible design, why was the one in this PR
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### Command used to generate this PR:**_(Applicable only to SDK release
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### Checklists
- [ ] Added impacted package name to the issue description
- [ ] Does this PR needs any fixes in the SDK Generator?** _(If so,
create an Issue in the
[Autorest/typescript](https://github.com/Azure/autorest.typescript)
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- [ ] Added a changelog (if necessary)

Author: lemonicetea

.github/CODEOWNERS

@@ -180,6 +180,9 @@
 # PRLabel: %Cognitive - Metrics Advisor
 /sdk/metricsadvisor/ @KarishmaGhiya @jeremymeng
 
+# PRLabel: %Cognitive - Content Safety
+/sdk/contentsafety/ @bowgong @mengai @minjuewu
+
 # PRLabel: %Search
 /sdk/search/ @dgetu @xirzec
 

sdk/contentsafety/ai-content-safety-rest/CHANGELOG.md

@@ -1,5 +1,5 @@
 # Release History
 
-## 1.0.0-beta.1 (Unreleased)
+## 1.0.0-beta.1 (2023-09-28)
 
 - This is the initial beta release for Azure AI Content Safety, see README.md for details.