Upgrade postgres driver to 42.2.19.

Original pull request: #961.

Author: schauder

pom.xml

@@ -38,7 +38,7 @@
 		<mariadb-java-client.version>2.6.0</mariadb-java-client.version>
 		<mssql.version>7.0.0.jre8</mssql.version>
 		<mysql-connector-java.version>5.1.41</mysql-connector-java.version>
-		<postgresql.version>42.0.0</postgresql.version>
+		<postgresql.version>42.2.19</postgresql.version>
 		<oracle.version>19.6.0.0</oracle.version>
 
 		<!-- test utilities-->