Add configuration for Stale GitHub app (#27)

Signed-off-by: Scott Rigby <scott@r6by.com>

.github/stale.yml

@@ -0,0 +1,16 @@
+# Number of days of inactivity before an issue becomes stale
+daysUntilStale: 30
+# Number of days of inactivity before a stale issue is closed
+daysUntilClose: 14
+# Issues with these labels will never be considered stale
+exemptLabels:
+  - lifecycle/frozen
+staleLabel: lifecycle/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
+  recent activity. It will be closed if no further activity occurs. Any further update will
+  cause the issue/pull request to no longer be considered stale. Thank you for your contributions.
+# Comment to post when closing a stale issue. Set to `false` to disable
+closeComment: >
+  This issue is being automatically closed due to inactivity.