[chronojump] howto_compile.txt: Replace broken git clone URL with GNOME Gitlab URL

[Andre Klapper <aklapper src gnome org>]

commit cfad659ee627b8678e3060f6159cab41e5ccc0e9
Author: Andre Klapper <a9016009 gmx de>
Date:   Sun May 24 19:51:53 2020 +0200

    howto_compile.txt: Replace broken git clone URL with GNOME Gitlab URL

 howto_compile.txt | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
---
diff --git a/howto_compile.txt b/howto_compile.txt
index 587924ad..739d91ae 100644
--- a/howto_compile.txt
+++ b/howto_compile.txt
@@ -19,7 +19,7 @@ MACOSX
 
 install cerbero
 
-git clone git://git.gnome.org/chronojump
+git clone https://gitlab.gnome.org/GNOME/chronojump.git
 
 start cerbero shell
 #this works from terminal or from ssh