Bump postgresql from 42.3.6 to 42.4.0

Bumps [postgresql](https://github.com/pgjdbc/pgjdbc) from 42.3.6 to 42.4.0.
- [Release notes](https://github.com/pgjdbc/pgjdbc/releases)
- [Changelog](https://github.com/pgjdbc/pgjdbc/blob/master/CHANGELOG.md)
- [Commits](pgjdbc/pgjdbc@REL42.3.6...REL42.4.0)

---
updated-dependencies:
- dependency-name: org.postgresql:postgresql
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>

core/pom.xml

@@ -546,7 +546,7 @@ Copyright (c) 2012 Jeremy Long. All Rights Reserved.
                 <dependency>
                     <groupId>org.postgresql</groupId>
                     <artifactId>postgresql</artifactId>
-                    <version>42.3.6</version>
+                    <version>42.4.0</version>
                 </dependency>
             </dependencies>
             <build>