Update README

Author: alexeyzimarev

README.md

@@ -2,7 +2,7 @@
 
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-| master | [![](https://img.shields.io/github/workflow/status/restsharp/RestSharp/Build%20and%20deploy)](https://github.com/restsharp/RestSharp/actions?query=workflow%3A%22Build+and+deploy%22) |
+| dev | [![](https://img.shields.io/github/workflow/status/restsharp/RestSharp/Build%20and%20deploy)](https://github.com/restsharp/RestSharp/actions?query=workflow%3A%22Build+and+deploy%22) |
 | docs | [![Netlify Status](https://img.shields.io/netlify/ae5b8e6e-32d9-4cdc-8a39-ca12ff2948f3?label=docs)](https://app.netlify.com/sites/restsharp/deploys) |
 
 ### Nuget