[Docs] README is missing `connectProtocol` for Postgres

[koeberlue]

When using the Postgres example from the README all Pods will crash with this error:

Unable to load configuration: config file corrupted: Persistence.DataStores[default](value).SQL.ConnectProtocol: zero value, Persistence.DataSt
ores[visibility](value).SQL.ConnectProtocol: zero value.

This can be easily fixed by setting connectProtocol: "tcp" for the datastores, as it can be seen in charts/temporal/values/values.postgresql.yaml.

For a new user it would be great if the example from the README already had this configured correctly.