Traefik and Caddy routes of applications now retry a failed connection
on another container, and the rolling update waits a configurable drain
time (default 5 seconds) after the new container is healthy before it
stops the old containers. The wait is skipped when no old container runs
or when the proxy labels changed, because the proxy drops a route that
two containers define differently.
Fixes#8627
Andras Bacsai
a3712f8902