[librsvg] CONTRIBUTING.md: fix internal link

[Federico Mena Quintero <federico src gnome org>]

commit a33f7a79d41b97db3985d3633ddaa1122ae512c3
Author: Federico Mena Quintero <federico gnome org>
Date:   Wed Apr 25 07:35:36 2018 -0500

    CONTRIBUTING.md: fix internal link

 CONTRIBUTING.md | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
---
diff --git a/CONTRIBUTING.md b/CONTRIBUTING.md
index bfb104cf..51530491 100644
--- a/CONTRIBUTING.md
+++ b/CONTRIBUTING.md
@@ -4,7 +4,7 @@ Contributing to librsvg
 Thank you for looking in this file!  There are different ways of
 contributing to librsvg, and we appreciate all of them.
 
-* [Source repository](#source-code)
+* [Source repository](#source-repository)
 * [Reporting bugs](#reporting-bugs)
 * [Feature requests](#feature-requests)
 * [Hacking on librsvg](#hacking-on-librsvg)