Fix Python version badge.

Author: stephanmg

README.rst

@@ -6,7 +6,7 @@ pyABC
    :width: 30 %
    :align: center
 
-![Python](https://img.shields.io/badge/Python-%3E%3D3.10-blue?logo=python&logoColor=white)
+[![Python](https://img.shields.io/badge/Python-%3E%3D3.10-blue?logo=python&logoColor=white)]
 
 |CI| |docs| |codecov| |pypi| |doi| |black|