docs: use buymeacoffee icon from flatbadgen

Signed-off-by: Rong Sen Ng (motss) <wes.ngrongsen@gmail.com>

README.md

@@ -6,7 +6,7 @@
 
 <hr />
 
-<a href="https://www.buymeacoffee.com/RLmMhgXFb" target="_blank" rel="noopener noreferrer"><img src="https://www.buymeacoffee.com/assets/img/custom_images/orange_img.png" alt="Buy Me A Coffee" style="height: 20px !important;width: auto !important;" ></a>
+[![buymeacoffee][buymeacoffee-badge]][buymeacoffee-url]
 [![tippin.me][tippin-me-badge]][tippin-me-url]
 [![Follow me][follow-me-badge]][follow-me-url]
 [![Join Discord][join-discord-badge]][join-discord-url]
@@ -262,6 +262,7 @@ Not tested on the following browsers but it should work with all the polyfills n
 [boolean-mdn-url]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Boolean?utm_source=github.com&amp;utm_medium=referral
 
 <!-- Badges -->
+[buymeacoffee-badge]: https://flat.badgen.net/badge/icon/buymeacoffee?icon=buymeacoffee&label=motss
 [tippin-me-badge]: https://badgen.net/badge/%E2%9A%A1%EF%B8%8Ftippin.me/@igarshmyb/F0918E
 [follow-me-badge]: https://flat.badgen.net/twitter/follow/igarshmyb?icon=twitter
 [join-discord-badge]: https://badgen.net/discord/members/ps8mCrvTKR?label=app-datepicker&icon=discord
@@ -282,6 +283,7 @@ Not tested on the following browsers but it should work with all the polyfills n
 [coc-badge]: https://flat.badgen.net/badge/code%20of/conduct/pink
 
 <!-- Links -->
+[buymeacoffee-url]: https://www.buymeacoffee.com/RLmMhgXFb
 [tippin-me-url]: https://tippin.me/@igarshmyb
 [follow-me-url]: https://twitter.com/igarshmyb?utm_source=github.com&amp;utm_medium=referral&amp;utm_content=motss/app-datepicker
 [join-discord-url]: https://discord.gg/ps8mCrvTKR