Update change log

Author: jim-easterbrook

CHANGELOG.txt

@@ -1,6 +1,6 @@
 python-gphoto2 - Python interface to libgphoto2
 http://github.com/jim-easterbrook/python-gphoto2
-Copyright (C) 2014-18  Jim Easterbrook  jim@jim-easterbrook.me.uk
+Copyright (C) 2014-19  Jim Easterbrook  jim@jim-easterbrook.me.uk
 
 This program is free software: you can redistribute it and/or modify
 it under the terms of the GNU General Public License as published by
@@ -15,6 +15,13 @@ GNU General Public License for more details.
 You should have received a copy of the GNU General Public License
 along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
+Changes in 2.0.0:
+  1/ COMPATIBILITY CHANGE: gp_log_add_func and use_python_logging now return a
+     Python object which must be stored until logging is no longer needed.
+  2/ Added cam-conf-view-gui & wait-for-event examples. Thanks to the users who
+     contributed these.
+  3/ Various minor bug fixes and improvements.
+
 Changes in 1.9.0:
   1/ Enabled use of context callback functions such as
      gp_context_set_progress_funcs.