add stale workflow using the workflow template (sigstore#2175)

Signed-off-by: Carlos Tadeu Panato Junior <ctadeu@gmail.com>

Signed-off-by: Carlos Tadeu Panato Junior <ctadeu@gmail.com>

.github/workflows/stale.yml

@@ -0,0 +1,29 @@
+name: "Close stale issues/pull requests"
+on:
+  schedule:
+  - cron: "30 1 * * *"
+
+jobs:
+  stale:
+    permissions:
+      issues: write
+      pull-requests: write
+
+    runs-on: ubuntu-latest
+
+    steps:
+    - uses: actions/stale@9c1b1c6e115ca2af09755448e0dbba24e5061cc8 # v5.1.1
+      with:
+        repo-token: ${{ secrets.GITHUB_TOKEN }}
+        stale-issue-message: 'This issue is stale because it has been open 60 days with no activity. Remove stale label or comment or this will be closed in 5 days.'
+        stale-pr-message: 'This PR is stale because it has been open 30 days with no activity. Remove stale label or comment or this will be closed in 10 days.'
+        close-issue-message: 'This issue was closed because it has been stalled for 5 days with no activity.'
+        close-pr-message: 'This PR was closed because it has been stalled for 10 days with no activity.'
+        stale-issue-label: 'no-issue-activity'
+        exempt-issue-labels: 'bug,core feature,enhancement,good first issue,help wanted,needs discussion'
+        stale-pr-label: 'no-pr-activity'
+        exempt-pr-labels: 'awaiting-approval,work-in-progress'
+        days-before-pr-stale: '30'
+        days-before-pr-close: '10'
+        days-before-issue-stale: '60'
+        days-before-close: '5'