`meltano upgrade` says `You must update Meltano to get new plugins updates.` when discovery version is bumped
[2020-05-28 10:35:36,356|D|MainThread|urllib3.connectionpool] Starting new HTTPS connection (1): www.meltano.com:443
[2020-05-28 10:35:36,731|D|MainThread|urllib3.connectionpool] https://www.meltano.com:443 "GET /discovery.yml HTTP/1.1" 200 32088
[2020-05-28 10:35:36,876|W|MainThread|root] You must update Meltano to get new plugins updates.
[2020-05-28 10:35:36,994|D|MainThread|root] Successfully compiled topics
Presumably because PluginDiscoveryService.__version__
hasn't been reloaded yet and still holds the old version.