Update README.md

Author: AndreiDrang

README.md

@@ -9,6 +9,7 @@
 [![Downloads](https://static.pepy.tech/badge/python3-capsolver/month)](https://pepy.tech/project/python3-capsolver)
 [![Static Badge](https://img.shields.io/badge/docs-Sphinx-green?label=Documentation&labelColor=gray)](https://andreidrang.github.io/python3-capsolver/)
 
+[![Maintainability](https://api.codeclimate.com/v1/badges/3c30167b5fb37a0775ea/maintainability)](https://codeclimate.com/github/AndreiDrang/python3-capsolver/maintainability)
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 [![codecov](https://codecov.io/gh/AndreiDrang/python3-capsolver/branch/main/graph/badge.svg?token=2L4VVIF4G8)](https://codecov.io/gh/AndreiDrang/python3-capsolver)