Adding stale issue bot.

_adjective_
(of food) no longer fresh and pleasant to eat; hard, musty, or dry.
`"stale bread"`

.github/stale.yml

@@ -0,0 +1,17 @@
+# Six months, minus 5 days, inactivity before an issue becomes stale
+daysUntilStale: 175
+# 5 days of inactivity before a stale issue is closed
+daysUntilClose: 5
+# Issues with these labels will never be considered stale
+exemptLabels:
+  - pinned
+  - security
+# Label to use when marking an issue as stale
+staleLabel: wontfix
+# 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
+  recent activity. It will be closed in 5 days if no further activity occurs. Thank you
+  for your contributions.
+# Comment to post when closing a stale issue. Set to `false` to disable
+closeComment: false