minor: add codecov badge

Author: ruslan-korneev

README.md

@@ -1,7 +1,7 @@
 # FastAPI Template
 
 [![CI](https://github.com/ruslan-korneev/fastapi-template/actions/workflows/ci.yml/badge.svg)](https://github.com/ruslan-korneev/fastapi-template/actions/workflows/ci.yml)
-[![codecov](https://codecov.io/gh/ruslan-korneev/fastapi-template/branch/main/graph/badge.svg)](https://codecov.io/gh/ruslan-korneev/fastapi-template)
+[![codecov](https://codecov.io/gh/ruslan-korneev/fastapi-template/graph/badge.svg?token=VIO9X50Y7A)](https://codecov.io/gh/ruslan-korneev/fastapi-template)
 [![Python 3.13+](https://img.shields.io/badge/python-3.13+-blue.svg)](https://www.python.org/downloads/)
 [![FastAPI](https://img.shields.io/badge/FastAPI-0.115-009688.svg?logo=fastapi)](https://fastapi.tiangolo.com)
 [![Ruff](https://img.shields.io/endpoint?url=https://raw.githubusercontent.com/astral-sh/ruff/main/assets/badge/v2.json)](https://github.com/astral-sh/ruff)