EN-1281: upgrade JDBC driver version
EN-1281: upgrade JDBC driver version

A param we want to use cancelSignalTimeout requires 9.4.1209 or higher:
https://jdbc.postgresql.org/documentation/94/connect.html

This upgrade bumps us from JDBC 4.1 to 4.2, which probably is fine. It's
included in Java SE 8.

socrata-platform/soql-postgres-adapter