[totem] README: fix dead link to GStreamer documentation

[Jordan Petridis <jpetridis src gnome org>]

commit ed5cdb892d5a5ae72a18f693346736c0b9e2a696
Author: Tim-Philipp Müller <tim centricular com>
Date:   Mon Jun 22 12:32:36 2020 +0100

    README: fix dead link to GStreamer documentation

 README | 6 ++----
 1 file changed, 2 insertions(+), 4 deletions(-)
---
diff --git a/README b/README
index 5b8c7bc9c..017859b1f 100644
--- a/README
+++ b/README
@@ -47,13 +47,11 @@ UI help by Seth Nickell <snickell stanford edu>
 
 Automatic GStreamer codec installation (optional)
 ================================================================
-- requires GStreamer core and gst-plugins-base >= 0.10.12
 - calls (via GStreamer) a predefined external helper script (which is to be
   installed by the distro and can be defined via gst-plugins-base's configure
   script when building gst-plugins-base) with details of missing GStreamer
-  plugins. See
-  
http://gstreamer.freedesktop.org/data/doc/gstreamer/head/gst-plugins-base-libs/html/gst-plugins-base-libs-gstpbutilsinstallplugins.html#id511743
-  for more information on how this all works together.
+  plugins. For more information on how this all works together see
+  https://gstreamer.freedesktop.org/documentation/pbutils/gstpbutilsinstallplugins.html
 
 BUGS
 ====