[gtk-doc] Update bug-report url.

[Stefan Sauer <stefkost src gnome org>]

commit 1178838e996d6be98bceab0c38af03a5917ba3c0
Author: Stefan Sauer <ensonic users sf net>
Date:   Mon May 27 16:47:56 2019 +0200

    Update bug-report url.
    
    Fixes #83

 configure.ac | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
---
diff --git a/configure.ac b/configure.ac
index 26ec6a2..69c1597 100644
--- a/configure.ac
+++ b/configure.ac
@@ -5,7 +5,7 @@ dnl We're using a two digit number for the releases and
 dnl a three digit number for the development version
 m4_define(gtk_doc_version, 1.30.1)
 
-AC_INIT([gtk-doc],[gtk_doc_version],[http://bugzilla.gnome.org/enter_bug.cgi?product=gtk-doc],[gtk-doc])
+AC_INIT([gtk-doc],[gtk_doc_version],[https://gitlab.gnome.org/GNOME/gtk-doc/issues],[gtk-doc])
 
 AC_CONFIG_MACRO_DIR([m4])
 AC_CONFIG_SRCDIR([gtk-doc.pc.in])