Update CHANGELOG for v1.10.68

***NO_CI***

Author: nfbot

CHANGELOG.md

@@ -1,8 +1,8 @@
 # Changelog
 
-## [**Changes available only in 'Preview' NuGet packages:**](https://github.com/nanoframework/System.Net/tree/HEAD)
+## [v1.10.66](https://github.com/nanoframework/System.Net/tree/v1.10.66) (2024-01-16)
 
-[Full Changelog](https://github.com/nanoframework/System.Net/compare/v1.10.64...HEAD)
+[Full Changelog](https://github.com/nanoframework/System.Net/compare/v1.10.64...v1.10.66)
 
 **Implemented enhancements:**