[gtkmm] configure.ac: Update bug report address

[Kjell Ahlstedt <kjellahl src gnome org>]

commit 1a46f86d4f8bb6d43860e25b0950bb2db203105f
Author: Kjell Ahlstedt <kjellahlstedt gmail com>
Date:   Fri Oct 26 16:07:03 2018 +0200

    configure.ac: Update bug report address

 configure.ac | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
---
diff --git a/configure.ac b/configure.ac
index 05141b1c..ade6cb36 100644
--- a/configure.ac
+++ b/configure.ac
@@ -16,7 +16,7 @@
 ## along with this library.  If not, see <http://www.gnu.org/licenses/>.
 
 AC_INIT([gtkmm], [3.93.0],
-        [http://bugzilla.gnome.org/enter_bug.cgi?product=gtkmm],
+        [https://gitlab.gnome.org/GNOME/gtkmm/issues/],
         [gtkmm], [http://www.gtkmm.org/])
 AC_PREREQ([2.59])