add code quality badge (#201)

.github/workflows/PR_CI.yml

@@ -49,8 +49,6 @@ jobs:
     steps:
       - name: Checkout repo
         uses: actions/checkout@v2
-        with:
-          ref: ${{ github.head_ref }}
 
       - name: autoyapf
         id: autoyapf

README.md

@@ -11,6 +11,7 @@
    
    [![Build](https://github.com/hpcaitech/ColossalAI/actions/workflows/PR_CI.yml/badge.svg)](https://github.com/hpcaitech/ColossalAI/actions/workflows/PR_CI.yml)
    [![Documentation](https://readthedocs.org/projects/colossalai/badge/?version=latest)](https://colossalai.readthedocs.io/en/latest/?badge=latest)
+   [![codebeat badge](https://codebeat.co/badges/bfe8f98b-5d61-4256-8ad2-ccd34d9cc156)](https://codebeat.co/projects/github-com-hpcaitech-colossalai-main)
 </div>
 An integrated large-scale model training system with efficient parallelization techniques.