Bump postgresql from 42.2.14 to 42.2.15 in /modules/junit-jupiter

Bumps [postgresql](https://github.com/pgjdbc/pgjdbc) from 42.2.14 to 42.2.15.
- [Release notes](https://github.com/pgjdbc/pgjdbc/releases)
- [Changelog](https://github.com/pgjdbc/pgjdbc/blob/master/CHANGELOG.md)
- [Commits](pgjdbc/pgjdbc@REL42.2.14...REL42.2.15)

Signed-off-by: dependabot[bot] <[email protected]>

modules/junit-jupiter/build.gradle

@@ -15,7 +15,7 @@ dependencies {
     testCompile 'org.assertj:assertj-core:3.16.1'
     testCompile 'org.junit.jupiter:junit-jupiter-params:5.6.2'
 
-    testRuntime 'org.postgresql:postgresql:42.2.14'
+    testRuntime 'org.postgresql:postgresql:42.2.15'
     testRuntime 'mysql:mysql-connector-java:8.0.21'
     testRuntime 'org.junit.jupiter:junit-jupiter-engine:5.6.2'
 }