Remove stale workflow (#5167)

.github/workflows/stale.yml

@@ -1,31 +0,0 @@
-name: Stale
-
-on:
-  schedule:
-    # run weekly on sunday
-    - cron: "0 0 * * 0"
-  workflow_dispatch:
-
-permissions: {}
-
-jobs:
-  label:
-    name: Label issues and PRs
-
-    runs-on: ubuntu-slim
-
-    permissions:
-      issues: write
-      pull-requests: write
-
-    steps:
-      - uses: actions/stale@v10
-        with:
-          days-before-stale: 60
-          days-before-close: -1 # Don't close anything
-          exempt-issue-labels: rfc,nostale,help wanted
-          exempt-all-milestones: true
-          exempt-all-assignees: true
-          operations-per-run: 1000
-          stale-issue-label: inactive
-          stale-pr-label: inactive