Bump org.postgresql:postgresql from 42.6.0 to 42.7.0

Bumps [org.postgresql:postgresql](https://github.com/pgjdbc/pgjdbc) from 42.6.0 to 42.7.0.
- [Release notes](https://github.com/pgjdbc/pgjdbc/releases)
- [Changelog](https://github.com/pgjdbc/pgjdbc/blob/master/CHANGELOG.md)
- [Commits](pgjdbc/pgjdbc@REL42.6.0...REL42.7.0)

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

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

omnij-rpc/build.gradle

@@ -30,7 +30,7 @@ dependencies {
     implementation ("org.apache.groovy:groovy-sql:${groovyVersion}") {
         transitive = false
     }
-    implementation 'org.postgresql:postgresql:42.6.0'
+    implementation 'org.postgresql:postgresql:42.7.0'
 
     testImplementation project(':omnij-dsl')
     testImplementation 'com.xlson.groovycsv:groovycsv:1.3'   // Used by Omni STO tests