Bump postgresql from 42.4.1 to 42.4.3 in /oap-server-bom

Bumps [postgresql](https://github.com/pgjdbc/pgjdbc) from 42.4.1 to 42.4.3.
- [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/REL42.4.1...REL42.4.3)

---
updated-dependencies:
- dependency-name: org.postgresql:postgresql
  dependency-type: direct:production
...
Signed-off-by: Ndependabot[bot] <support@github.com>

oap-server-bom/pom.xml

@@ -66,7 +66,7 @@
         <mvel.version>2.4.8.Final</mvel.version>
         <commons-beanutils.version>1.9.4</commons-beanutils.version>
         <flatbuffers-java.version>1.12.0</flatbuffers-java.version>
-        <postgresql.version>42.4.1</postgresql.version>
+        <postgresql.version>42.4.3</postgresql.version>
         <jetcd.version>0.5.3</jetcd.version>
         <testcontainers.version>1.15.3</testcontainers.version>
         <armeria.version>1.18.0</armeria.version>