docs: Add codecov badge (#18)

README.md

@@ -6,8 +6,9 @@
 [![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)
 
 [![Documentation Status](https://readthedocs.org/projects/ssec-python-project-template/badge/?version=latest)](https://ssec-python-project-template.readthedocs.io/en/latest/?badge=latest)
-[![CI](https://github.com/uw-ssec/python-project-template/actions/workflows/ci.yml/badge.svg)](https://github.com/uw-ssec/python-project-template/actions/workflows/ci.yml)
 [![pre-commit.ci status](https://results.pre-commit.ci/badge/github/uw-ssec/python-project-template/main.svg)](https://results.pre-commit.ci/latest/github/uw-ssec/python-project-template/main)
+[![CI](https://github.com/uw-ssec/python-project-template/actions/workflows/ci.yml/badge.svg)](https://github.com/uw-ssec/python-project-template/actions/workflows/ci.yml)
+[![codecov](https://codecov.io/gh/uw-ssec/python-project-template/graph/badge.svg?token=13LYMLQBZL)](https://codecov.io/gh/uw-ssec/python-project-template)
 
 Python project repository template for developing python package. This template
 includes a basic structure for developing a python package, including a license,