chore: Add codecov badge

README.md

@@ -7,7 +7,7 @@
 
 [![CI](https://github.com/frappe/erpnext/actions/workflows/server-tests.yml/badge.svg?branch=develop)](https://github.com/frappe/erpnext/actions/workflows/server-tests.yml)
 [![Open Source Helpers](https://www.codetriage.com/frappe/erpnext/badges/users.svg)](https://www.codetriage.com/frappe/erpnext)
-[![Coverage Status](https://coveralls.io/repos/github/frappe/erpnext/badge.svg?branch=develop)](https://coveralls.io/github/frappe/erpnext?branch=develop)
+[![codecov](https://codecov.io/gh/frappe/erpnext/branch/develop/graph/badge.svg?token=0TwvyUg3I5)](https://codecov.io/gh/frappe/erpnext)
 
 [https://erpnext.com](https://erpnext.com)