This adds a metric, kubeproxy_sync_proxy_rules_last_queued_timestamp,
that captures the last time a change was queued to be applied to the
proxy. This matches the healthz logic, which fails if a pending change
is stale.
This allows us to write alerts that mirror healthz.
Signed-off-by: Casey Callendrello <cdc@redhat.com>
2e1a884bf3