[gnome-latex] GitLab migration: update HACKING file

[Sébastien Wilmet <swilmet src gnome org>]

commit b5e4cf1ae962137d01ad0e961a814de7fe9afdeb
Author: Sébastien Wilmet <swilmet gnome org>
Date:   Fri Feb 23 19:03:44 2018 +0100

    GitLab migration: update HACKING file

 HACKING | 11 ++++++-----
 1 file changed, 6 insertions(+), 5 deletions(-)
---
diff --git a/HACKING b/HACKING
index 49bb06b..50459d4 100644
--- a/HACKING
+++ b/HACKING
@@ -1,12 +1,13 @@
 How to contribute to GNOME LaTeX
 ================================
 
-The Git version control system is used. Read the following wiki pages to know
-how to create and send patches to bugzilla, and the conventions for the commit
-messages:
+GNOME LaTeX is hosted on the GNOME GitLab instance, you can fork the repository
+and then do a merge request:
+
+    https://gitlab.gnome.org/GNOME/gnome-latex
+
+Read the following wiki page to know the conventions for the commit messages:
 
-    https://wiki.gnome.org/Git
-    https://wiki.gnome.org/Git/WorkingWithPatches
     https://wiki.gnome.org/Git/CommitMessages
 
 Code conventions