Bump postgresql from 42.3.1 to 42.4.1 in /service

Bumps [postgresql](https://github.com/pgjdbc/pgjdbc) from 42.3.1 to 42.4.1.
- [Release notes](https://github.com/pgjdbc/pgjdbc/releases)
- [Changelog](https://github.com/pgjdbc/pgjdbc/blob/master/CHANGELOG.md)
- [Commits](https://github.com/pgjdbc/pgjdbc/compare/REL42.3.1...REL42.4.1)

---
updated-dependencies:
- dependency-name: org.postgresql:postgresql
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <support@github.com>
diff --git a/service/pom.xml b/service/pom.xml
index b6325d6..c79f000 100644
--- a/service/pom.xml
+++ b/service/pom.xml
@@ -44,7 +44,7 @@
         <derby.version>10.14.1.0</derby.version>
         <eclipselink.version>2.6.0</eclipselink.version>
         <mysql.java.version>5.1.47</mysql.java.version>
-        <postgresql.version>42.3.1</postgresql.version>
+        <postgresql.version>42.4.1</postgresql.version>
         <livy.core.version>0.3.0</livy.core.version>
         <elasticsearch-rest-client.version>6.2.4</elasticsearch-rest-client.version>
         <jackson-databind.version>2.9.9.3</jackson-databind.version>