Add "Buy me a coffee" image

Author: albertas

Diff for: README.md

@@ -7,6 +7,7 @@
 <a href="https://pypi.org/project/deadcode/"><img alt="PyPI" src="https://img.shields.io/pypi/v/deadcode"></a>
 <a href="https://pepy.tech/project/deadcode"><img alt="Downloads" src="https://static.pepy.tech/badge/deadcode"></a>
 <a href="https://github.com/albertas/deadcode/blob/main/LICENSE"><img alt="License: AGPLv3" src="https://raw.githubusercontent.com/albertas/deadcode/main/docs/_static/AGPLv3-license.svg"></a>
+<a href='https://ko-fi.com/V7V21681GD' target='_blank'><img height='36' style='border:0px;height:36px;' src='https://storage.ko-fi.com/cdn/kofi6.png?v=6' border='0' alt='Buy Me a Coffee at ko-fi.com' /></a>
 </p>