readme: update ko-fi

Author: ayufan

README.md

@@ -12,7 +12,7 @@ properly. Feel free to create an issue to debug those.
 
 ## Buy me a Coffee
 
-<a href='https://ko-fi.com/ayufan' target='_blank'><img height='30' style='border:0px;height:40px;' src='https://az743702.vo.msecnd.net/cdn/kofi3.png?v=0' alt='Buy Me a Coffee at ko-fi.com' /></a>
+[![ko-fi](https://ko-fi.com/img/githubbutton_sm.svg)](https://ko-fi.com/Y8Y8GCP24)
 
 If you found it useful :)
 

RELEASE.md

@@ -1,5 +1,5 @@
 ## Buy me a Coffee
 
-<a href='https://ko-fi.com/ayufan' target='_blank'><img height='30' style='border:0px;height:40px;' src='https://az743702.vo.msecnd.net/cdn/kofi3.png?v=0' alt='Buy Me a Coffee at ko-fi.com' /></a>
+[![ko-fi](https://ko-fi.com/img/githubbutton_sm.svg)](https://ko-fi.com/Y8Y8GCP24)
 
 If you found it useful :)