docs: Fix link to CGO wiki page

The Go wiki is no longer hosted on GitHub, and has moved to go.dev. See https://github.com/golang/go/wiki/

Author: jordelver

CONTRIBUTING.md

@@ -55,7 +55,7 @@ If it is of some complexity, the contributor is expected to maintain and support
 
 Any non-trivial code change needs to update an open [issue](https://github.com/gohugoio/hugo/issues). A non-trivial code change without an issue reference with one of the labels `bug` or `enhancement` will not be merged.
 
-Note that we do not accept new features that require [CGO](https://github.com/golang/go/wiki/cgo).
+Note that we do not accept new features that require [CGO](https://go.dev/wiki/cgo).
 We have one exception to this rule which is LibSASS.
 
 **Bug fixes are, of course, always welcome.**