feat(notification): add comment on “old” MR to notify the assignees there is pending work

Only old MR (for now 10 days without activity), which are not wip, not client
related, and with an assignee, add a friendly comment.

closes: cubicweb/cubicweb#101
2 jobs for topic/default/notification in 26 seconds (queued for 28 seconds)
Status Job ID Name Coverage
  Lint
failed #86044
lint_black

00:00:24

passed #86045
lint_flake8

00:00:26

 
Name Stage Failure
failed
lint_black Lint
No job log