docs: add github sponsor button

README.md

@@ -52,6 +52,7 @@ It is highly recommended to use the 1.x version until a stable version of 2.0 is
 
 Wiki.js is an open source project that has been made possible due to the generous contributions by community [backers](https://github.com/Requarks/wiki/blob/master/BACKERS.md). If you are interested in supporting this project, please consider [becoming a patron](https://www.patreon.com/requarks), donating to our [OpenCollective](https://opencollective.com/wikijs), via [Paypal](https://www.paypal.com/cgi-bin/webscr?cmd=_s-xclick&hosted_button_id=FLV5X255Z9CJU&source=url) or via Ethereum (`0xe1d55c19ae86f6bcbfb17e7f06ace96bdbb22cb5`).
   
+  [![Become a Sponsor](https://img.shields.io/badge/donate-github-lightgrey.svg?style=popout&logo=github)](https://github.com/users/NGPixel/sponsorship)
   [![Become a Patron](https://img.shields.io/badge/donate-patreon-orange.svg?style=popout&logo=patreon)](https://www.patreon.com/requarks)
   [![Donate on OpenCollective](https://img.shields.io/badge/donate-open%20collective-blue.svg?style=popout&logo=data:image/svg+xml;base64,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)](https://opencollective.com/wikijs)
   [![Donate via Paypal](https://img.shields.io/badge/donate-paypal-blue.svg?style=popout&logo=paypal)](https://www.paypal.com/cgi-bin/webscr?cmd=_s-xclick&hosted_button_id=FLV5X255Z9CJU&source=url)