cync_lan (Home Assistant custom_component) v2.10.3

Requires cync-lan 0.10.4, which fixes a third way cloud passthrough went
quiet - this one after 2.10.2 was supposed to have settled it, and only after a
device reconnects to the cloud.

The library flag that means "relay but keep controlling" was cleared whenever
the proxy stopped, leaving the flag that means "relay and stay silent" set. The
reconnect path and the idle-connection watcher both stop and restart the proxy
as ordinary business, so a session went silent on its first cloud reconnect and
stayed that way until Home Assistant restarted.

Unlike the 2.9.0 version of this bug, it does not switch the house off. Commands
go out over two randomly chosen device connections, so one is lost only when
both draws happen to be silent ones. On the install this was found on, 21 of 46
connections were affected, which is about one command in five doing nothing -
close enough to flaky hardware or a weak mesh to be worth saying plainly: if
you have cloud passthrough on and have been blaming your lights, this was
probably us.

The version floor is why this release exists. 0.10.4 fixes it, but a Home
Assistant install that already has 0.10.3 satisfies the old >=0.10.3
requirement and never upgrades on its own.