Added auto-stale config

.github/stale.yml

@@ -0,0 +1,16 @@
+# Number of days of inactivity before an issue becomes stale
+daysUntilStale: 31
+# Number of days of inactivity before a stale issue is closed
+daysUntilClose: 14
+# Issues with these labels will never be considered stale
+# exemptLabels:
+#   - enhancement
+#   - bug
+# Label to use when marking an issue as stale
+staleLabel: stale
+# Comment to post when marking an issue as stale. Set to `false` to disable
+markComment: >
+  This issue has been automatically marked as stale because it has not had
+  activity in 31 days. It will be closed if no further activity occurs in 14 days.
+# Comment to post when closing a stale issue. Set to `false` to disable
+closeComment: false