chore(github): add stalebot

Signed-off-by: Alexander Alemayhu <alexander@alemayhu.com>

.github/workflows/stale_bot.yml

@@ -0,0 +1,51 @@
+# SPDX-License-Identifier: Apache-2.0
+
+# Copied from https://raw.githubusercontent.com/instructlab/community/refs/heads/main/.github/workflows/stale_bot.yml
+name: 'Close stale issues and PRs'
+
+on:
+  schedule:
+    - cron: '30 1 * * *'
+
+env:
+  LC_ALL: en_US.UTF-8
+
+defaults:
+  run:
+    shell: bash
+
+permissions:
+  contents: read
+
+jobs:
+  stale:
+    permissions:
+      issues: write
+      pull-requests: write
+    runs-on: ubuntu-latest
+    steps:
+      - name: 'Harden Runner'
+        uses: step-security/harden-runner@0080882f6c36860b6ba35c610c98ce87d4e2f26f # v2.10.2
+        with:
+          egress-policy: audit # TODO: change to 'egress-policy: block' after couple of runs
+
+      - name: 'Stale Action'
+        uses: actions/stale@28ca1036281a5e5922ead5184a1bbf96e5fc984e # v9.0.0
+        with:
+          stale-issue-label: 'stale'
+          stale-issue-message: >
+            This issue has been automatically marked as stale because it has not had activity within 60 days.
+            It will be automatically closed if no further activity occurs within 30 days.
+          close-issue-message: >
+            This issue has been automatically closed due to inactivity. Please feel free to reopen if you feel it is still relevant!
+          days-before-issue-stale: 60
+          days-before-issue-close: 30
+          exempt-issue-labels: 'ongoing'
+          stale-pr-label: 'stale'
+          stale-pr-message: >
+            This pull request has been automatically marked as stale because it has not had activity within 60 days.
+            It will be automatically closed if no further activity occurs within 30 days.
+          close-pr-message: >
+            This pull request has been automatically closed due to inactivity. Please feel free to reopen if you intend to continue working on it!
+          days-before-pr-stale: 60
+          days-before-pr-close: 30