Fix a typo in CONTRIBUTING.md

The URL `git://github.com/USERNAME/hugo.git` is invalid; it should instead be either `https://github.com/USERNAME/hugo.git` or `[email protected]:USERNAME/hugo.git`. I chose the latter for this PR.
gohugoio · Aug 7, 2020 · f3cb0be · f3cb0be
1 parent bffc4e1
commit f3cb0be
Showing 1 changed file with 1 addition and 1 deletion.
diff --git a/CONTRIBUTING.md b/CONTRIBUTING.md
@@ -144,7 +144,7 @@ Now, to make a change to Hugo's source:
 1. Add your fork as a new remote (the remote name, "fork" in this example, is arbitrary):
 
     ```bash
-    git remote add fork git://github.com/USERNAME/hugo.git
+    git remote add fork git@github.com:USERNAME/hugo.git
     ```
 
 1. Push the changes to your new remote: