github: add stale bot to eval repo

.github/stale_bot.yml

@@ -0,0 +1,49 @@
+# SPDX-License-Identifier: Apache-2.0
+
+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@91182cccc01eb5e619899d80e4e971d6181294a7 # v2.10.1
+        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 90 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: 90
+          days-before-issue-close: 30
+          stale-pr-label: 'stale'
+          stale-pr-message: >
+            This pull request has been automatically marked as stale because it has not had activity within 90 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: 90
+          days-before-pr-close: 30