update links

Author: jmckenna

en/announcements/announcements_archive.txt

@@ -705,19 +705,19 @@ for more details and head to :ref:`download` to obtain a copy.
 **2009-07-24 - MapServer 5.4.2 is released**
 
 MapServer 5.4.2 has been released.  See the
-`Changelog <https://trac.osgeo.org/mapserver/browser/tags/rel-5-4-2/mapserver/HISTORY.TXT>`__
+`Changelog <https://github.com/MapServer/MapServer/blob/rel-5-4-2/HISTORY.TXT>`__
 for more details and head to :ref:`download` to obtain a copy.
 
 **2009-06-01 - MapServer 5.4.1 is released**
 
 MapServer 5.4.1 has been released.  See the
-`Changelog <https://trac.osgeo.org/mapserver/browser/tags/rel-5-4-1/mapserver/HISTORY.TXT>`__
+`Changelog <https://github.com/MapServer/MapServer/blob/rel-5-4-1/HISTORY.TXT>`__
 for more details and head to :ref:`download` to obtain a copy.
 
 **2009-04-22 - MapServer 5.4 is released**
 
 MapServer 5.4 has been released.  See the
-`Changelog <https://trac.osgeo.org/mapserver/browser/tags/rel-5-4-0/mapserver/HISTORY.TXT>`__
+`Changelog <https://github.com/MapServer/MapServer/blob/rel-5-4-0/HISTORY.TXT>`__
 for more details and head to :ref:`download` to obtain a copy.
 
 **2009-03-26 - MapServer 5.2.2 and 4.10.4 security fixes are released**