Update codecov badge

Author: jeromegamez

README.md

@@ -7,7 +7,7 @@
 [![Tests](https://github.com/kreait/firebase-php/actions/workflows/tests.yml/badge.svg)](https://github.com/kreait/firebase-php/actions/workflows/tests.yml)
 [![Integration Tests](https://github.com/kreait/firebase-php/actions/workflows/integration-tests.yml/badge.svg)](https://github.com/kreait/firebase-php/actions/workflows/integration-tests.yml)
 [![Emulator Tests](https://github.com/kreait/firebase-php/actions/workflows/emulator-tests.yml/badge.svg)](https://github.com/kreait/firebase-php/actions/workflows/emulator-tests.yml)
-[![codecov](https://codecov.io/gh/kreait/firebase-php/branch/main/graph/badge.svg)](https://codecov.io/gh/kreait/firebase-php)
+[![codecov](https://codecov.io/gh/kreait/firebase-php/graph/badge.svg?token=Azl8QCvbTQ)](https://codecov.io/gh/kreait/firebase-php)
 [![Sponsor](https://img.shields.io/static/v1?logo=GitHub&label=Sponsor&message=%E2%9D%A4&color=ff69b4)](https://github.com/sponsors/jeromegamez)
 
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