[ci skip] add stale bot configuration

.github/stale.yml

@@ -0,0 +1,13 @@
+daysUntilStale: 60
+daysUntilClose: 7
+exemptLabels:
+  - "status: accepted"
+staleLabel: "resolution: stale"
+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.
+closeComment: >
+  This issue has been automatically closed because it has not had activity in
+  a long time. If the issue still applies to the most recent supported
+  version, please open a new issue referencing this original issue.