docs: update readme

Author: R-unic

README.md

@@ -17,7 +17,7 @@ You can also demo the language using the Cosmo bot in [my Discord server](https:
 
 ## Contributing
 
-There is a guide about how to contribute [here](https://github.com/cosmo-lang/cosmo/wiki) on our Wiki.<br>
+There is a guide about how to contribute [here](https://cosmo-lang.dev/docs) on our website.<br>
 You can find any documentation you might need to contribute [here](https://cosmo-lang.github.io/cosmo). It's a page automatically generated by Crystal containing documentation for all classes, modules, etc.
 
 1. [Fork it](https://github.com/R-unic/cosmo/fork)