add liberapay

Author: extrawurst

README.md

@@ -224,6 +224,8 @@ The key bindings can be customized: See [Key Config](KEY_CONFIG.md) on how to se
 
 [![github](https://img.shields.io/badge/-GitHub%20Sponsors-fafbfc?logo=GitHub%20Sponsors)](https://github.com/sponsors/extrawurst)
 
+<a href="https://liberapay.com/extrawurst/donate"><img alt="Donate using Liberapay" src="https://liberapay.com/assets/widgets/donate.svg"></a>
+
 ## 13. <a name="inspiration"></a> Inspiration <small><sup>[Top ▲](#table-of-contents)</sup></small>
 
 - [lazygit](https://github.com/jesseduffield/lazygit)