Update changelog

CHANGELOG.rst

+Unreleased changes
+------------------
+
+Version 1
+---------
+
+1.2.0 / 2019-11-25
+~~~~~~~~~~~~~~~~~~
+
+* Top 10 events are now saved
+* Added automatic ELOG entry for massive evenets, monitored in ``ztplot.py``
+
+1.1.1 / 2019-10-23
+~~~~~~~~~~~~~~~~~~
+
+* Several bugfixes and improvements
+
+
+1.1.0 / 2019-10-03
+~~~~~~~~~~~~~~~~~~
+
+* Several bugfixes and improvements
+
+
+1.0.0 / 2019-06-29
+~~~~~~~~~~~~~~~~~~
+
+* First major release, using supervisord