chore: remove sponsors section (#2544)

* chore: Remove Gold sponsors section

Because they don't sponsor us anymore.

* chore: Remove route4me logo

---------

Co-authored-by: Koy Zhuang <koy@ko8e24.top>

README.md

@@ -58,7 +58,7 @@ A large collection of showcase projects are included in [awesome-docsify](https:
 
 ## Contributing
 
-See [CONTRIBUTING.md](./CONTRIBUTING.md).
+See [CONTRIBUTING.md](CONTRIBUTING.md).
 
 ## Backers
 
@@ -75,12 +75,9 @@ Thank you for supporting this project! ❤️ [[Become a sponsor](https://openco
 ## Contributors
 
 This project exists thanks to all the people who contribute. [[Contribute](CONTRIBUTING.md)].
+
 <a href="https://github.com/docsifyjs/docsify/graphs/contributors"><img src="https://opencollective.com/docsify/contributors.svg?width=890" /></a>
 
 ## License
 
 [MIT](LICENSE)
-
-## Special Thanks
-
-A preview of Docsify's PR and develop branch is <a href="https://vercel.com/?utm_source=docsifyjs&utm_campaign=oss" target="_blank">Powered by <img src="https://cdn.jsdelivr.net/gh/docsifyjs/docsify/docs/_media/vercel_logo.svg" alt="Vercel" width="133px"></a>

docs/README.md

@@ -25,10 +25,6 @@ Check out the [Showcase](https://github.com/docsifyjs/awesome-docsify#showcase)
 
 Please consider donating if you think docsify is helpful to you or that my work is valuable. I am happy if you can help me [buy a cup of coffee](https://github.com/QingWei-Li/donate). :heart:
 
-### Gold sponsors
-
-[![](_images/Route4Me.png ':size=200')](https://route4me.com/ 'Best Route Planning and Route Optimization Software')
-
 ## Community
 
 Users and the development team are usually in the [Discord server](https://discord.gg/3NwKFyR).