Update permissions for Birkenfeld.

Misc/developers.txt

@@ -20,7 +20,8 @@ Permissions History
 - Reinhold Birkenfeld was given SF tracker permissions on 28 May 2005
   by RDH.  Since the beginning of 2005, he has been active in discussions
   on python-dev and has submitted a dozen patch reviews.  The permissions
-  add the ability to change tracker status and to attach patches.
+  add the ability to change tracker status and to attach patches.  On
+  3 June 2005, this was expanded by RDH to include checkin permissions.
 
 - Terry Reedy was given SF tracker permissions on 7 Apr 2005 by RDH.