Upgrade JDBC Smart driver to the latest (42.6.x) upstream PGJDBC driver

[yugabyte-ci]

Jira Link: DB-6609

[rob-bygrave]

Note that without this update the current driver does NOT support Java Virtual Threads. This update is a high priority for folks wanting to use Virtual Threads.

After that upgrade to 42.6.x then the Yugabyte specific changes should NOT use synchronized and instead use org.postgresql.jdbc.ResourceLock - refer to: pgjdbc/pgjdbc#2635

I can prepare a PR to use org.postgresql.jdbc.ResourceLock but we need the upgrade to 42.6.x first.

[rob-bygrave]

Also, I'd suggest that it would be useful to add a specific label for the "JDBC Smart driver" component so that all issues relating to the driver can easily be found. It is going to be fairly important that this driver fork is kept up to date with pgjdbc.