Actualizar README.md

Author: sir-gon

README.md

@@ -7,6 +7,7 @@
 ![GitHub](https://img.shields.io/github/license/sir-gon/algorithm-exercises-java)
 ![GitHub language count](https://img.shields.io/github/languages/count/sir-gon/algorithm-exercises-java)
 ![GitHub top language](https://img.shields.io/github/languages/top/sir-gon/algorithm-exercises-java)
+[![CodeFactor](https://www.codefactor.io/repository/github/sir-gon/algorithm-exercises-java/badge)](https://www.codefactor.io/repository/github/sir-gon/algorithm-exercises-java)
 [![codecov](https://codecov.io/gh/sir-gon/algorithm-exercises-java/graph/badge.svg?token=7QAS85D3HB)](https://codecov.io/gh/sir-gon/algorithm-exercises-java)
 [![FOSSA Status](https://app.fossa.com/api/projects/git%2Bi.8713187.xyz%2Fsir-gon%2Fprojecteuler-java.svg?type=shield)](https://app.fossa.com/projects/git%2Bi.8713187.xyz%2Fsir-gon%2Fprojecteuler-java?ref=badge_shield)