Bump postgresql from 42.5.3 to 42.5.4 (jenkinsci#1415)

Author: dependabot[bot]

pom.xml

@@ -294,7 +294,7 @@
     <dependency>
       <groupId>org.postgresql</groupId>
       <artifactId>postgresql</artifactId>
-      <version>42.5.3</version>
+      <version>42.5.4</version>
       <scope>test</scope>
       <exclusions>
         <!-- Upper bounds with Guava -->