[gimp-help] Update bug tracker link

[Alexandre Prokoudine <aprokoudine src gnome org>]

commit dd0c080ef71706b8c1f7721567e9624bcaff96e4
Author: Alexandre Prokoudine <alexandre prokoudine gmail com>
Date:   Fri Sep 7 09:22:13 2018 +0000

    Update bug tracker link

 src/help-missing.xml | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)
---
diff --git a/src/help-missing.xml b/src/help-missing.xml
index 63b16a725..5bbad0f56 100644
--- a/src/help-missing.xml
+++ b/src/help-missing.xml
@@ -27,8 +27,8 @@
          side of the footer, to help users filing bug reports.
          Bug: 711318
       -->
-    <ulink id="reportbug" url="https://bugzilla.gnome.org/enter_bug.cgi?product=GIMP-manual";>
-      Report an error in Bugzilla
+    <ulink id="reportbug" url="https://gitlab.gnome.org/GNOME/gimp-help/issues";>
+      Report an error in the bug tracker
     </ulink> and let us know.
   </para>
 </appendix>