Update README.md

Author: andrey-helldar

README.md

@@ -11,7 +11,6 @@ Visualise your routes in pretty format.
 </p>
 
 [![Stable Version][badge_stable]][link_packagist]
-[![Unstable Version][badge_unstable]][link_packagist]
 [![Total Downloads][badge_downloads]][link_packagist]
 [![Github Workflow Status][badge_build]][link_build]
 [![License][badge_license]][link_license]
@@ -106,8 +105,6 @@ This package is licensed under the [MIT License](LICENSE).
 
 [badge_stable]:     https://img.shields.io/github/v/release/TheDragonCode/pretty-routes?label=stable&style=flat-square
 
-[badge_unstable]:   https://img.shields.io/badge/unstable-dev--main-orange?style=flat-square
-
 [link_build]:       https://github.com/TheDragonCode/pretty-routes/actions
 
 [link_license]:     LICENSE