Fixed missing Patreon image

The previous image was not available anymore. Replaced it with a direct link to the one on https://www.patreon.com/brand/downloads

Author: davidluzgouveia

README.md

@@ -30,7 +30,7 @@ If you like the content you find here, and want to support more content like it,
 
 If you'd like to contribute financially towards the effort (or any of my other OSS work) aside from purchasing the books, I do have a [patreon](https://www.patreon.com/getify) that I would always appreciate your generosity towards.
 
-<a href="https://www.patreon.com/getify">[![patreon.png](https://s13.postimg.org/k9nkc5thz/become_a_patron_button.png)](https://www.patreon.com/getify)</a>
+<a href="https://www.patreon.com/getify">[![patreon.png](https://c5.patreon.com/external/logo/become_a_patron_button.png)](https://www.patreon.com/getify)</a>
 
 ## In-person Training