Update charm libraries (#48)

Co-authored-by: Github Actions <[email protected]>

lib/charms/traefik_k8s/v1/ingress_per_unit.py

@@ -82,7 +82,7 @@ def _on_ingress_revoked(self, event: IngressPerUnitRevokedForUnitEvent):
 
 # Increment this PATCH version before using `charmcraft publish-lib` or reset
 # to 0 if you are raising the major API version
-LIBPATCH = 16
+LIBPATCH = 17
 
 log = logging.getLogger(__name__)
 
@@ -254,6 +254,7 @@ def __init__(self, charm: CharmBase, relation_name: str = DEFAULT_RELATION_NAME)
         observe(rel_events.relation_created, self._handle_relation)
         observe(rel_events.relation_joined, self._handle_relation)
         observe(rel_events.relation_changed, self._handle_relation)
+        observe(rel_events.relation_departed, self._handle_relation)
         observe(rel_events.relation_broken, self._handle_relation_broken)
         observe(charm.on.leader_elected, self._handle_upgrade_or_leader)  # type: ignore
         observe(charm.on.upgrade_charm, self._handle_upgrade_or_leader)  # type: ignore