releng: update patch release dates for 1.19

Signed-off-by: Carlos Panato <[email protected]>

Author: cpanato

data/releases/schedule.yaml

@@ -76,11 +76,14 @@ schedules:
       targetDate: 2020-12-18
       note: "Tagging Issue https://groups.google.com/g/kubernetes-dev/c/dNH2yknlCBA"
 - release: 1.19
-  next: 1.19.15
-  cherryPickDeadline: 2021-09-10
-  targetDate: 2021-09-15
+  next: 1.19.16
+  cherryPickDeadline: 2021-10-22
+  targetDate: 2021-10-27
   endOfLifeDate: 2021-10-28
   previousPatches:
+    - release: 1.19.15
+      cherryPickDeadline: 2021-09-10
+      targetDate: 2021-09-15
     - release: 1.19.14
       cherryPickDeadline: 2021-08-07
       targetDate: 2021-08-11