Prepare release for System.ClientModel 1.8.1 (#53802)

Author: m-nash

sdk/core/System.ClientModel/CHANGELOG.md

@@ -1,14 +1,11 @@
 # Release History
 
-## 1.9.0-beta.1 (Unreleased)
-
-### Features Added
-
-### Breaking Changes
+## 1.8.1 (2025-11-10)
 
 ### Bugs Fixed
 
-### Other Changes
+- Fixed an issue with JsonPatch.TryGetValue throwing instead of returning false in some cases.
+- Fixed an issue with JsonPatch decoding special characters in json when using GetString.
 
 ## 1.8.0 (2025-10-31)
 

sdk/core/System.ClientModel/src/System.ClientModel.csproj

@@ -2,7 +2,7 @@
 
   <PropertyGroup>
     <Description>Contains building blocks for clients that call cloud services.</Description>
-    <Version>1.9.0-beta.1</Version>
+    <Version>1.8.1</Version>
     <!--The ApiCompatVersion is managed automatically and should not generally be modified manually.-->
     <ApiCompatVersion>1.8.0</ApiCompatVersion>
     <Nullable>enable</Nullable>