pg-upgrade-logical: Add the "Before upgrade" section and upgrade command for the "Registry" cluster.
- Vars: Set
pg_target_dbname
equalspg_source_dbname
.- Since they are actually always equal. Since logical replication is configured for a standby cluster that was originally prepared using physical replication.
- README: Add the "Before upgrade" section and upgrade command for the "Registry" cluster.
- Since the database name of the Registry cluster differs from the default value