added codecov badge

Author: Jurj-Bogdan

README.md

@@ -11,6 +11,7 @@ Logging Error Handler for DotKernel
 [![GitHub license](https://img.shields.io/github/license/dotkernel/dot-errorhandler)](https://github.com/dotkernel/dot-errorhandler/blob/3.0/LICENSE)
 
 [![Build Static](https://github.com/dotkernel/dot-errorhandler/actions/workflows/static-analysis.yml/badge.svg?branch=3.0)](https://github.com/dotkernel/dot-errorhandler/actions/workflows/static-analysis.yml)
+[![codecov](https://codecov.io/gh/dotkernel/dot-errorhandler/branch/3.0/graph/badge.svg?token=0KIJARS5RS)](https://codecov.io/gh/dotkernel/dot-errorhandler)
 
 [![SymfonyInsight](https://insight.symfony.com/projects/cf1f8d89-f230-4157-bc8b-7cce20c75454/big.svg)](https://insight.symfony.com/projects/cf1f8d89-f230-4157-bc8b-7cce20c75454)