Add lifecycle management for PRs and issues (#1135)
Add lifecycle management for PRs and issues (#1135)

PRs and issues will be marked as stale after 6 months, and closed
automatically after another 6 months.

Signed-off-by: Antonin Bas <fb45519bfd86140bf21e06c2676c295f783a518b@vmware.com>
p4lang/behavioral-model,p4lang/behavioral-model,p4lang/behavioral-model,p4lang/behavioral-model,p4lang/behavioral-model