Fix broken CI badge

Co-Authored-By: James Cooke <[email protected]>

Author: adamchainz

README.rst

@@ -5,7 +5,7 @@ Django-MySQL
 .. image:: https://img.shields.io/readthedocs/django-mysql?style=for-the-badge
    :target: https://django-mysql.readthedocs.io/en/latest/
 
-.. image:: https://img.shields.io/github/workflow/status/adamchainz/django-mysql/CI/main?style=for-the-badge
+.. image:: https://img.shields.io/github/actions/workflow/status/adamchainz/django-mysql/main.yml?branch=main&style=for-the-badge
    :target: https://github.com/adamchainz/django-mysql/actions?workflow=CI
 
 .. image:: https://img.shields.io/badge/Coverage-100%25-success?style=for-the-badge