pgsql 16.x Etcd Reports Version that breaks Patroni #928

Discussion with Patroni explains the issue and workaround of patroni/dcs/etcd3.py

patroni/patroni#3385

Summary:

curl --cacert /etc/pki/tls/certs/ca.crt --cert /etc/pki/tls/certs/host.crt --key /etc/pki/tls/private/host.key https://my-host-psqldb03.mydomain.com:2379/version -X GET -d '{}'

Curl returns {"etcdserver":"3.5.21","etcdcluster":"3.0.0"}

Patroni uses 3.0.0 to formulate the URL to get the cluster state. The URL returns 404 because etcd deprecated the API endpoint assuming it's a very old version of etcd API.

Curl needs to return something like {"etcdserver":"3.5.21","etcdcluster":"3.5.0"}