adds stubs for Pdo\Pgsql

[aldilop]

these are taken from the documentation in https://www.php.net/manual/en/class.pdo-pgsql.php, which can be sourced back to https://github.com/php/php-src/blob/master/ext/pdo_pgsql/pgsql_driver.stub.php

[isfedorov]

@aldilop Thank you for the PR! Could you please update StubsMap with command docker compose -f docker-compose.yml run test_runner /usr/local/bin/php tests/Tools/generate-stub-map (or use your local interpreter) and commit result map file along with other changers?

[aldilop]

docker compose -f docker-compose.yml run test_runner /usr/local/bin/php tests/Tools/generate-stub-map

Thanks! I added to the CLASSES array