Add support target_session_attrs

[AlexanderSabirov]

Problem

When specifying multiple hosts in a PostgreSQL cluster, it is possible to connect to the server in read-only mode.

Solution

When specifying multiple hosts in a PostgreSQL cluster, it is necessary to pass the parameter target_session_attrs. This PR adds support for that parameter.

Checklist

• I have read the contributing guide and understand what's expected of me
• I have run this code in development and it appears to resolve the stated issue
• This PR includes tests, or tests are not required/relevant for this PR
• This PR has no interface changes (e.g. macros, cli, logs, json artifacts, config files, adapter interface, etc) or this PR has already received feedback and approval from Product or DX