doc: Update README

Author: jcdcdev

.github/README.md

@@ -18,6 +18,9 @@ The following editors are currently supported:
 - Textstring
 - Textarea
 
+> [!NOTE]
+> Version 16 is not released yet.
+
 ## Quick Start
 
 1. Install the [NuGet package](https://www.nuget.org/packages/jcdcdev.Umbraco.ReadingTime) in your Umbraco CMS website project.