add stale bot

.github/stale.yml

@@ -0,0 +1,11 @@
+daysUntilStale: 7
+daysUntilClose: 7
+exemptLabels:
+  - bug
+  - enhancement
+staleLabel: wontfix
+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.
+
+  该 issue 在近期内缺少更新或答复，如果仍然缺少更新或响应，issue 将被关闭。