Set low priority for scheduled runs (#839)

Author: castrodd

eng/ci/official-build.yml

@@ -1,5 +1,5 @@
 schedules:
-  - cron: '0 20 * * *'
+  - cron: "0 5 * * *"
     displayName: Nightly Build
     branches:
       include:
@@ -44,6 +44,9 @@ extends:
       name: 1es-pool-azfunc
       image: 1es-windows-2022
       os: windows
+      ${{ if eq( variables['Build.Reason'], 'Schedule' ) }}:
+        demands:
+        - Priority -equals Low
 
     stages:
       - stage: Build

eng/ci/public-build.yml

@@ -1,5 +1,5 @@
 schedules:
-  - cron: '0 0 * * *'
+  - cron: "0 5 * * *"
     displayName: Nightly Build
     branches:
       include:
@@ -31,6 +31,9 @@ extends:
       name: 1es-pool-azfunc-public
       image: 1es-windows-2022
       os: windows
+      ${{ if eq( variables['Build.Reason'], 'Schedule' ) }}:
+        demands:
+        - Priority -equals Low
 
     sdl:
       codeql: