As suggested by @hjmjohnson, the probot-stale GitHub App has been installed on the ITK repository. 
 
 
As described in its documentation, this adds a bot that does the following:
- 
After a period of inactivity, a label will be applied to mark an issue as stale, and optionally a comment will be posted to notify contributors that the Issue or Pull Request will be closed.
 - 
If the Issue or Pull Request is updated, or anyone comments, then the stale label is removed and nothing further is done until it becomes stale again.
 - 
If no more activity occurs, the Issue or Pull Request will be automatically closed with an optional comment.
 
Please review this PR to set up its configuration.