Copy schedule to stable branches.

.azure-pipelines/azure-pipelines.yml

@@ -14,12 +14,24 @@ pr:
 
 schedules:
   - cron: 0 8 * * *
-    displayName: Nightly
+    displayName: Nightly (main)
     always: true
     branches:
       include:
         - main
-        - stable-*
+  - cron: 0 10 * * *
+    displayName: Nightly (active stable branches)
+    always: true
+    branches:
+      include:
+        - stable-2
+        - stable-3
+  - cron: 0 11 * * 0
+    displayName: Weekly (old stable branches)
+    always: true
+    branches:
+      include:
+        - stable-1
 
 variables:
   - name: checkoutPath