chore: add stale workflow

Author: ota-meshi

.github/workflows/stale.yml

@@ -0,0 +1,32 @@
+name: Close stale issues and PRs
+on:
+  schedule:
+    - cron: "30 1 * * *"
+
+permissions:
+  issues: write
+  pull-requests: write
+
+jobs:
+  stale:
+    if: github.repository == 'sveltejs/eslint-plugin-svelte'
+    name: Close stale issues with missing information
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/stale@v8
+        with:
+          any-of-labels: "needs repro,needs info,needs more info"
+          days-before-stale: 60
+          days-before-close: 14
+          stale-issue-message: This issue is is stale because it missing information and has been open for 60 days with no activity.
+          stale-pr-message: This PR is is stale because it missing information and has been open for 60 days with no activity.
+          close-issue-message: >
+            This issue has been automatically closed because we haven't received a
+            response from the original author 🙈. This automation helps keep the issue
+            tracker clean from issues that aren't actionable. Please reach out if you
+            have more information for us! 🙂
+          close-pr-message: >
+            This PR has been automatically closed because we haven't received a
+            response from the original author 🙈. This automation helps keep the issue
+            tracker clean from PRs that aren't actionable. Please reach out if you
+            have more information for us! 🙂