Update CHANGELOG for v1.0.0

***NO_CI***

Author: nfbot

CHANGELOG.md

@@ -1,5 +1,17 @@
 # Changelog
 
+## [**Changes available only in 'Preview' NuGet packages:**](https://github.com/nanoframework/lib-nanoFramework.WebServer/tree/HEAD)
+
+[Full Changelog](https://github.com/nanoframework/lib-nanoFramework.WebServer/compare/v1.0.0-preview.20...HEAD)
+
+**Documentation and other chores:**
+
+- Update 1 nuget dependencies [\#18](https://github.com/nanoframework/lib-nanoFramework.WebServer/pull/18)
+
+## [v1.0.0-preview.20](https://github.com/nanoframework/lib-nanoFramework.WebServer/tree/v1.0.0-preview.20) (2021-03-05)
+
+[Full Changelog](https://github.com/nanoframework/lib-nanoFramework.WebServer/compare/v1.0.0-preview.18...v1.0.0-preview.20)
+
 ## [v1.0.0-preview.18](https://github.com/nanoframework/lib-nanoFramework.WebServer/tree/v1.0.0-preview.18) (2021-03-02)
 
 [Full Changelog](https://github.com/nanoframework/lib-nanoFramework.WebServer/compare/v1.0.0-preview.15...v1.0.0-preview.18)