continuous-integration/drone/push Build is passingDetails
- `pychromecast.get_chromecasts` returns both a list of devices and a
browser object. Since the Chromecast plugin is the most likely culprit
of the excessive number of open MDNS sockets, it seems that we may
need to explicitly stop discovery on the browser and close the
ZeroConf object after the discovery is done.
- I was still using an ancient version of pychromecast on my RPi4, and I
didn't notice that more recent versions implemented several breaking
changes. Adapted the code to cope with those changes.