Remove stale coverage from README.md

README.md

@@ -7,7 +7,6 @@
 [![downloads](https://pepy.tech/badge/taichi)](https://pepy.tech/project/taichi)
 [![CI](https://github.com/taichi-dev/taichi/actions/workflows/testing.yml/badge.svg)](https://github.com/taichi-dev/taichi/actions/workflows/testing.yml)
 [![Nightly Release](https://github.com/taichi-dev/taichi/actions/workflows/release.yml/badge.svg)](https://github.com/taichi-dev/taichi/actions/workflows/release.yml)
-[![Python Codecov Status](https://img.shields.io/codecov/c/github/taichi-dev/taichi?label=Python%20Coverage&logo=codecov)](https://codecov.io/gh/taichi-dev/taichi/src/master)
 <a href="https://join.slack.com/t/taichicommunity/shared_invite/zt-14ic8j6no-Fd~wKNpfskXLfqDr58Tddg"><img src="https://img.shields.io/badge/join-us%20on%20slack-gray.svg?longCache=true&logo=slack&colorB=red"></a>
 
 ```shell