Update CHANGELOG for v1.0.6

***NO_CI***

Author: nfbot

CHANGELOG.md

@@ -2,7 +2,15 @@
 
 ## [**Changes available only in 'Preview' NuGet packages:**](https://github.com/nanoframework/lib-nanoFramework.Networking.Sntp/tree/HEAD)
 
-[Full Changelog](https://github.com/nanoframework/lib-nanoFramework.Networking.Sntp/compare/v1.0.6-preview.9...HEAD)
+[Full Changelog](https://github.com/nanoframework/lib-nanoFramework.Networking.Sntp/compare/v1.0.6-preview.23...HEAD)
+
+**Documentation and other chores:**
+
+- Bumps nanoFramework.CoreLibrary from 1.2.6-preview.7 to 1.2.6-preview.16 [\#46](https://github.com/nanoframework/lib-nanoFramework.Networking.Sntp/pull/46)
+- Update readme.txt [\#45](https://github.com/nanoframework/lib-nanoFramework.Networking.Sntp/pull/45)
+
+## [v1.0.6-preview.23](https://github.com/nanoframework/lib-nanoFramework.Networking.Sntp/tree/v1.0.6-preview.23) (2019-06-23)
+[Full Changelog](https://github.com/nanoframework/lib-nanoFramework.Networking.Sntp/compare/v1.0.6-preview.9...v1.0.6-preview.23)
 
 **Documentation and other chores:**