Add monthly cron job (dotnet#11051)

This addition runs Sequester once per month to process all open issues. In that mode, it moves any open issues that haven't been rescheduled into the "backlog" sprint in Azure DevOps.

Author: BillWagner

.github/workflows/quest-bulk.yml

@@ -2,6 +2,7 @@ name: "bulk quest import"
 on:
   schedule:
     - cron: '0 10 * * *' # UTC time, that's 5:00 am EST, 2:00 am PST.
+    - cron: '0 9 6 * *'  # This is the morning of the 6th.
   workflow_dispatch:
     inputs:
       reason:
@@ -49,4 +50,4 @@ jobs:
           org: ${{ github.repository_owner }}
           repo: ${{ github.repository }}
           issue: '-1'
-          duration: ${{ github.event_name == 'workflow_dispatch' && github.event.inputs.duration || 5 }}
+          duration: ${{ github.event_name == 'workflow_dispatch' && github.event.inputs.duration || github.event.schedule == '0 9 6 * *' && -1 || 5 }}