Bump postgresql from 42.3.0 to 42.3.8

Bumps [postgresql](https://github.com/pgjdbc/pgjdbc) from 42.3.0 to 42.3.8.
- [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/REL42.3.0...REL42.3.8

)

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

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