patch-releases: Update cycle after May releases and EOL 1.18

Signed-off-by: Stephen Augustus <foo@auggie.dev>
Co-authored-by: Carlos Panato <ctadeu@gmail.com>

data/releases/schedule.yaml

@@ -1,16 +1,22 @@
 schedules:
 - release: 1.21
-  next: 1.21.1
-  cherryPickDeadline: 2021-05-07
-  targetDate: 2021-05-12
+  next: 1.21.2
+  cherryPickDeadline: 2021-06-12
+  targetDate: 2021-06-16
   endOfLifeDate: 2022-04-30
   previousPatches:
+    - release: 1.21.1
+      cherryPickDeadline: 2021-05-07
+      targetDate: 2021-05-12
 - release: 1.20
-  next: 1.20.7
-  cherryPickDeadline: 2021-05-07
-  targetDate: 2021-05-12
+  next: 1.20.8
+  cherryPickDeadline: 2021-06-12
+  targetDate: 2021-06-16
   endOfLifeDate: 2021-12-30
   previousPatches:
+    - release: 1.20.7
+      cherryPickDeadline: 2021-05-07
+      targetDate: 2021-05-12
     - release: 1.20.6
       cherryPickDeadline: 2021-04-09
       targetDate: 2021-04-14
@@ -30,11 +36,14 @@ schedules:
       cherryPickDeadline: "Tagging Issue https://groups.google.com/g/kubernetes-dev/c/dNH2yknlCBA"
       targetDate: 2020-12-18
 - release: 1.19
-  next: 1.19.11
-  cherryPickDeadline: 2021-05-07
-  targetDate: 2021-05-12
+  next: 1.19.12
+  cherryPickDeadline: 2021-06-12
+  targetDate: 2021-06-16
   endOfLifeDate: 2021-09-30
   previousPatches:
+    - release: 1.19.11
+      cherryPickDeadline: 2021-05-07
+      targetDate: 2021-05-12
     - release: 1.19.10
       cherryPickDeadline: 2021-04-09
       targetDate: 2021-04-14