Adding the date of Xena's PTG

Change-Id: Icfc09047152a74bd707ef0b1dfb7b11694851e54

doc/source/xena/schedule.rst

@@ -39,8 +39,8 @@ Virtual PTG
 
 .. This needs to be added to the schedule once we know when the event will be
 
-A virtual PTG will be held during this week. The Project Teams Gathering
-provides and opportunity for teams to collaborate
+A virtual PTG will be held during this week (Apr 19-23, 2021). The Project
+Teams Gathering provides and opportunity for teams to collaborate
 and plan, and discuss requirements for future releases.
 
 .. _x-1:

doc/source/xena/schedule.yaml

@@ -9,6 +9,8 @@ cycle:
 - end: '2021-04-23'
   name: R-24
   start: '2021-04-19'
+  x-project:
+    - x-ptg
 - end: '2021-04-30'
   name: R-23
   start: '2021-04-26'