update tests badge to v3

README.md

@@ -1,7 +1,7 @@
 <p align="center">
     <img src="https://raw.githubusercontent.com/pestphp/art/master/v3/banner.png" width="600" alt="PEST">
     <p align="center">
-        <a href="https://github.com/pestphp/pest/actions"><img alt="GitHub Workflow Status (master)" src="https://img.shields.io/github/actions/workflow/status/pestphp/pest/tests.yml?branch=2.x&label=Tests%202.x"></a>
+        <a href="https://github.com/pestphp/pest/actions"><img alt="GitHub Workflow Status (master)" src="https://img.shields.io/github/actions/workflow/status/pestphp/pest/tests.yml?branch=3.x&label=Tests%203.x"></a>
         <a href="https://packagist.org/packages/pestphp/pest"><img alt="Total Downloads" src="https://img.shields.io/packagist/dt/pestphp/pest"></a>
         <a href="https://packagist.org/packages/pestphp/pest"><img alt="Latest Version" src="https://img.shields.io/packagist/v/pestphp/pest"></a>
         <a href="https://packagist.org/packages/pestphp/pest"><img alt="License" src="https://img.shields.io/packagist/l/pestphp/pest"></a>