[gtk+] Bump gtk-doc dep to 1.20

[Matthias Clasen <matthiasc src gnome org>]

commit d3c8bd83d96113672ac6bf4f245d4c5c19d8deb3
Author: Matthias Clasen <mclasen redhat com>
Date:   Mon Feb 17 16:55:16 2014 -0500

    Bump gtk-doc dep to 1.20

 configure.ac |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/configure.ac b/configure.ac
index c9e86dc..1c0da29 100644
--- a/configure.ac
+++ b/configure.ac
@@ -1633,7 +1633,7 @@ AM_CONDITIONAL(HAVE_COLORD, test "x$have_colord" = "xyes")
 # Checks for gtk-doc and docbook-tools
 ##################################################
 
-GTK_DOC_CHECK([1.19.1],[--flavour no-tmpl])
+GTK_DOC_CHECK([1.20],[--flavour no-tmpl])
 
 AC_ARG_ENABLE(man,
               [AS_HELP_STRING([--enable-man],