Add stale bot

.github/stale.yml

@@ -0,0 +1,33 @@
+# Configuration for probot-stale - https://github.com/probot/stale
+
+# Number of days of inactivity before an Issue or Pull Request becomes stale
+daysUntilStale: 14
+
+# Number of days of inactivity before an Issue or Pull Request with the stale label is closed.
+# Set to false to disable. If disabled, issues still need to be closed manually, but will remain marked as stale.
+daysUntilClose: 7
+
+# Only issues or pull requests with all of these labels are check if stale. Defaults to `[]` (disabled)
+onlyLabels: []
+
+# Label to use when marking as stale
+staleLabel: stale
+
+# Comment to post when marking 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. Thank you
+  for your contributions.
+
+closeComment: >
+  This issue has been automatically closed because it has not had
+  any activity in the last 21 days. Feel free to re-open in case you would like to follow up.
+
+pulls:
+  markComment: >
+    This PR has been automatically marked as stale because it has not had
+    any activity in the last 14 days. It will be closed if no further activity occurs, thank you
+    for your contributions.
+  closeComment: >
+    This PR has been automatically closed because it has not had
+    any activity in the last 21 days. Feel free to re-open in case you would like to follow up.