feat: add stalebot config

.github/stale.yml

@@ -0,0 +1,23 @@
+limitPerRun: 30
+daysUntilStale: 30
+daysUntilClose: 7
+
+exemptLabels:
+  - pinned
+  - security
+  - "[Status] Maybe Later"
+
+exemptAssignees: true
+
+staleLabel: wontfix
+
+pulls:
+  markComment: >
+    This pull request has been automatically marked as stale because it has not had
+    recent activity. It will be closed if no further activity occurs. Thank you
+    for your contributions.
+issues:
+  markComment: >
+    This issue has been automatically marked as stale because it has not had
+    recent activity. It will be closed if no further activity occurs. Thank you
+    for your contributions.