Add a basic info into the release notes

Author: seberm

docs/releases.rst

@@ -5,6 +5,14 @@
 ======================
 
 
+The :ref:`/plugins/report/reportportal` plugin now handles the
+timestamps for ``custom`` and ``restraint`` results correctly. It
+should never happen that the result's ``end-time`` will be higher
+then the ``start-time``. It should be also ensured that the start
+time of all launch items is the same or higher then the start time
+of a parent item/launch.
+
+
 tmt-1.39.0
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~