Bump postgresql from 42.5.1 to 42.5.3 in /fhir-parent (#4181)

Bumps [postgresql](https://github.com/pgjdbc/pgjdbc) from 42.5.1 to 42.5.3.
- [Release notes](https://github.com/pgjdbc/pgjdbc/releases)
- [Changelog](https://github.com/pgjdbc/pgjdbc/blob/REL42.5.3/CHANGELOG.md)
- [Commits](pgjdbc/pgjdbc@REL42.5.1...REL42.5.3)

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

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fhir-parent/pom.xml

@@ -489,7 +489,7 @@
             <dependency>
                 <groupId>org.postgresql</groupId>
                 <artifactId>postgresql</artifactId>
-                <version>42.5.1</version>
+                <version>42.5.3</version>
             </dependency>
             <dependency>
                 <groupId>com.google.protobuf</groupId>