docs: fix broken contributors link in CONTRIBUTING.MD (#2337)

* Set contributors link to two dirs up so link to contributor graph works
* Hard code contributors link (implemented in the same way as README) to fix broken link

***NO_CI***

.github/CONTRIBUTING.md

@@ -47,7 +47,7 @@ You can also reach us at hello@wikijs.opencollective.com.
 ### Contributors
 
 Thank you to all the people who have already contributed to Wiki.js!
-<a href="graphs/contributors"><img src="https://opencollective.com/wikijs/contributors.svg?width=890" /></a>
+<a href="https://github.com/Requarks/wiki/graphs/contributors"><img src="https://opencollective.com/wikijs/contributors.svg?width=890" /></a>
 
 
 ### Backers