CI: remove stale workflow (#10409)

.github/workflows/stale.yml

@@ -1,52 +0,0 @@
-name: 'Manage stale issues'
-
-on:
-  schedule:
-  - cron: '0 0 * * *'
-
-permissions: {}
-jobs:
-  stale:
-    permissions:
-      issues: write # to close stale issues (actions/stale)
-      pull-requests: write # to close stale PRs (actions/stale)
-
-    runs-on: ubuntu-latest
-
-    steps:
-
-    - name: Stale Bot
-      uses: actions/stale@v8
-      with:
-        repo-token: ${{ secrets.GITHUB_TOKEN }}
-
-        # Number of days of inactivity before an issue or PR is considered stale
-        days-before-pr-stale: 15
-
-        days-before-issue-stale: 45
-
-
-        # Number of days of inactivity before a stale issue or PR is closed
-        days-before-pr-close: 30
-
-        days-before-issue-close: 90
-
-        # Issues or PRs with these labels will never be considered stale
-        exempt-pr-labels: stalebot ignore
-
-        exempt-issue-labels: stalebot ignore,help wanted
-
-        # Label to use when marking an issue or PR as stale
-        stale-pr-label: waiting
-
-        # Comment to post when marking an issue or PR as stale
-        stale-pr-message: |
-          Hi all! This thread has not had any recent activity.
-          Are there any updates? Thanks!
-
-        # Comment to post when closing a stale issue or PR
-        close-pr-message: |
-          Hi everyone.
-          This thread is being closed as there was no response to the previous prompt.
-          However, please leave a comment whenever you're ready to resume, so the thread can be reopened.
-          Thanks again!